Show HN: Web page that parses and explains the label on a bike tire (fahrrad-tools.de)

631 points by moasda ↗ HN
History: Last year I had to replace the tire on my bike, and I was surprised how difficult it was to find a suitable new tire. There were a lot of numbers written on the casing, so I googled what they meant. In the end I was successful, but I didn't want to do the same work again for the next bike after I've forgotten the details. So I wrote this website.

Technically, the web page is kept very simple, no frameworks, no templates, no website builder. It uses HTML5, CSS and JavaScript, and it privides a responsive layout for mobile usage.

I'm happy to receive feedback. If you have tried the label of your bike tire, and it doesn't work, please post it as well. Thanks!

184 comments

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This is really great!! Definitely something that would have helped me back in the day before I realized how complicated / annoying getting proper tires was.

I won't need it for my own bike anymore, but definitely when I get a new (used) one next.

Thanks for sharing, this looks really useful. I have started biking again recently and the labels on the tire are super confusing. Do you have any plans to extend this(attempt OCR or something)?

I tried looking at the source a bit and it seems like your markup is pretty clean, if a bit unreadable after minification. I liked the classes "question" and "answer". It looks like you are planning on using affiliate links to monetize it?

Thank you for the feedback. OCR is a great idea, for me it seems to be quite difficult to implement and probably requires a mobile app.

The affiliate links are just a side effect to pay for the hosting.

You could possibly do it server side. I would personally implement it as a Flask server that took an image, ran it through either Pytesseract (quick, got to manually preprocess, needs tesseract installed) or Easyocr (slower but works out the box) then send back the if and only if it was a valid tire-info-string to avoid people abusing it for other purposes.
Wow, thank you, I will check that.
You could use a simple client-side JS OCR library, like GOCR.js[0]. It may only work on good photos of relatively new tires with clearly printed text, and that's not always what bicycle tires look like when you're looking to replace it, so not sure how useful it'd be.

[0]: https://antimatter15.com/gocr.js/demo.html

Interesting approach, thank you. Sure, old tires might be hard to scan, but definitely worth to think about.
I tried to to use GOCR packaged with Ubuntu on playlists, expecting it to work well since it's computer output. But it turned out not working so well. I also tried scaling the text but that didn't fix it.
Can I ask why OCR, other than to learn something new. From a functionality standpoint you’ve hit the nail on the head. Some suggestions in this thread however start to take away from the appeal of the site. I suspect the target audience will much rather type out the dozen numbers/chars than they will attempt to mess around with taking a picture and having OCR take over. I’d be willing to bet the time to enter data is comparable and if there are any savings to be had from OCR (doubtful) it would be measured in seconds at best.

Identify the audience and build the product for it. A tech savvy audience (HN) would love to see OCR because we have nothing better to do than look for “latest cool gadgets”.

Good point, the page is designed for easy usage and beginners, rather than experts.
https://www.sheldonbrown.com/tire-sizing.html has (i think all?) of the edge cases you're going to encounter in any bike made after about 1925.
Thanks, this link definitely helps to cross-check if I got the mapping right.
For anyone else stumbling across this, sheldonbrown.com has a wealth of high-quality information about bicycles, and it's rare that I don't look there first.
100%. If I’m doing my own maintenance (for just about anything) or want to build up some Franken-bike, I read up on my Sheldon “thank god that website is still around” Brown.
Sheldon Brown is the go to for everything like this.

There are no affiliate links, and he went way beyond the company he worked on, it's a pure act of love and is super comprehensive. It's just info to help you.

I would caution people reading that site to double-check anything they see there, or simply consult a much, much older version from archive.org.

Sheldon passed over a decade ago, and the site has been modified over time by a guy named John Allen. He fancies himself an expert of similar caliber, but has a tiny fraction of the hands-on experience Sheldon did.

He's made a number of edits/additions injecting his personal opinion. For example: about belt drives, of which he clearly has no personal experience.

Huh, I had a look at the belt drive thing - Allen added that in 2012(!) when belt drives were still relatively new - Gates went mainstream around 2009, and Center Track appeared 2010-2011. At the time many more belt drives would have been retrofitted onto old bikes instead of frames designed for them. He may not have had the experience then, but should have by now...that definitely needs an edit.

And wow, over a decade indeed, I can't believe its been so long :(

(FWIW my main bike has been belt drive & Rohloff geared, dynamo lights for 6 years now, the reduced maintenance is great, I can just step on my bike and go)

Semi-tangential, I took my fixie to Harris Cyclery for a tuneup before it closed. Boy, was I floored when the guy working at the counter told me that fixies weren't cool anymore. Sheldon was a big part of my journey to riding fixed gear. I learned everything I know about bikes from his site and he even answered questions personally by email.

I'm pretty sure when the guy said fixies weren't cool, I heard Sheldon spin in his grave a little.

Don’t worry, fixies are still cool among a select bunch of people. I’ve never cared for them, but plenty still do. There is also a budding fixie racing community outside of the track (including crit and CX), which is simply terrifying to me.
Yeah the hipsters ride ill-fitting vintage steel racers now, some of the girls look so uncomfortable straining forward to reach the brake leaver. Fixed gear has gone back to being for a few enthusiasts and messengers and other bike weirdos like me. I’ve ridden one as a daily for years and years due to how awesome the virtually zero upkeep is, plus I personally find them safer, especially in winter.
This is the sort of websites we need more of. It's simple, fast and useful, and not monetized at the users' expense.
I tried to buy bike inner tubes on Amazon and I just could not do it. I would do a search, go to a product page, and the thing I wanted simply was not on that product page. I wound up going to a local bike shop and was in and out in less time than I had spent trying to find them online.
Yeah, tubes are complicated by the fact that one tube size fits more than one tire size, plus there are two different kinds of valve stems, and some contemporary wheels need extra long stems.

One favor you can do yourself is to start patching your tubes if you're not already doing so.

You are right, for the first time it's confusing to find the right tube as they fit to several tire sizes.
is there a trick? when I first started riding I got a bunch of patch kits. I'm doing this in the shop so I have plenty of time to clean the area, rough it up. clamps to make sure the patch is firmly set, etc. after about..10 tries? I just gave up. I am religiously for wringing the last bit of functionality out of something before burying it...but it just wasn't worth it.
Are you using self-adhesive patches or something that uses a tube of glue? I never got on with anything other than Rema's patches.
Indeed, the answer is Rema. There may be some other brands that are as good, but Rema forms an actual chemical bond between the patch and the rubber of the tire. The vulcanizing fluid prepares the surface of the tube so it will bond to the patch. Better living through chemistry.

Everything else, check. Roughing up the patch area, waiting a few minutes for the vulcanizing fluid to dry, squeezing the patch for a few seconds after applying.

I've never had a problem with the little sandpaper that comes with the kit.

The sandpaper used in most kits is near useless. The sheetmetal "rasp" rougheners work much better to get the mold release broken up.
While I commend anyone who takes the time to patch a tube, if you have kids/job/life/etc it is so much quicker and easier to just replace the tube. They can be bought for very little and fitted before you've even tracked down the hole on the old tube. If you are out on a longish ride, you probably want to be carrying full size spare tubes tucked in a pocket or bag anyway - patching at the roadside is not fun, and again takes far longer than just popping in new tube and getting on your way. Tubes with no air in them are very small/compact.

Over the past 20 years of riding a collection of ~10 bikes, I would be lucky if patching tubes would have saved me even 200 dollars. What your time is worth to you may be different, but for most working adults I don't think patching makes time-money-sense. Assuming you already have a pump, instead of ordering a patch kit to carry with you on rides or keep at home, just order one of whatever tube your bike needs (usually ~5-9 bucks), some tire levers (reusable, 5 bucks) and keep in drawer until day dawns you need it. The rare time I buy a new bike with a weird innertube I don't already have, I buy a couple of spares immediately with the bike.

That's fair, and you need a spare tube anyway because not all flats are repairable. I carry a spare tube and a patch kit, but typically patch the punctured tube at home. The patch kit is in case I get a second flat -- a vanishingly rare occurrence thanks to puncture resistant tires.

Each person has to satisfy their own sense of time and money, which I suspect is partially subjective for most of us. For instance I actually have spare time, and am not paid for working extra hours on my day job. Admittedly, being self sufficient for bike maintenance is part of "life" for me, and even when my kids needed more attentive care, I was always able to carve out 15 minutes to patch a tube.

> I carry a spare tube and a patch kit, but typically patch the punctured tube at home.

Paranoid me always carry two spare tubes, a patch kit and a puncture repair spray (it's supposed to inject a product that reinflates the tyre immediately, allowing me to keep riding and then go home without having to repair or remplace the tube, but since I've never had the opportunity to use it I can't tell if it's really effective).

Puncture resistant tires have really allowed me to be a bit more relaxed about flats. Also, fortunately I don't live in goat head country. Here in Wisconsin, a vital supply for fixing flats while on a ride is mosquito repellent.
> Here in Wisconsin, a vital supply for fixing flats while on a ride is mosquito repellent.

Where I am, in the south of France, as well. And they are of the really aggressive species!

Switched to tubeless last year, but prior to that I've patched a few as an emergency and tossed it when I get home. All of my patches held but I didn't trust a single one. $10/tube was cheap insurance against a potential disaster.

I do run latex on my gravel/cx bike and those go into the trash immediately as they're far more difficult to properly patch. Hurts a little more when you pay 2-3x the price though :(

Amazon's search is completely useless if you're looking for specific things. It simply ignores what you typed and throws random sponsored products at you.
Heh. Even in bicycle-rich countries like Germany and the Netherlands, these numbers are somehow still tricky. I guess it doesn't help that they are often hard to read and a lot of the numbers are actually redundant.

So yeah, useful! And my compliments for the neatness in your data privacy approach.

At one point I just took the old tyre into a bicycle repair shop and asked for the proper replacement, and the person who sold me one even managed to get the wrong one (they replaced it for the proper one afterwards of course). It used to be that most normal use bicycles all had the same tyre, and only racing bikes had those weird French style ones, but newer bicycles tend to have fatter tyres (which is not a bad development for sturdy day-to-day bicycles laden with groceries, an adult cyclist, and a child in front or behind the cyclist).

Great work. I've replaced several tires and every time it's the same ambiguous lookups followed by crossed fingers as I install the thing. I'm sure I'll use this page in the future
I like putting 700x32 tires on my bike. Haven't issue attention to the other numbers. Are they mostly redundant? Guessing for a casual rider they don't have much of an impact?
The ETRTO numbers are the most useful ones. If you just look on them, you're good to go.
Yeah, that 28" number is goofy. In Mountain bike terms, it's a 29er. For road usage, it's 700c. But the rest of the world, at least those who measure in mm, use 622.
Yes, the outer diameter is a bit more complicated. From this point of view, some bikes can use different tire sizes.
That's what I learned around 1984 from reading a book. 10 years before internet was a thing :) Have ignored all other numbers since then. Have not had any worse problem than some clerk might have given me a strange look when I bought tires referring to ETRTO numbers.
You're probably OK as 700x32 is a fairly common designation. The ETRTO for that tire is 32-622.
A somewhat important factor is if the tire is slick/smooth, knobby or in-between. For casual riding you probably want something in the middle so that it's fine on most surfaces.
Slick/smooth unless you're doing mud/snow. The tread compound matters a lot more than the tread pattern, until you're into sloppy stuff, and then the tread starts to matter.
Very nice. As a long time cyclist with a fondness for bikes thrown together from odd parts, finding suitable tires that are affordable is always an issue. I've learned that the ETRTO number is the only thing I need to know. Virtually all modern tires provide that number.

There have only been some rare cases such as a 1963 Schwinn repack cruiser, where I needed to do a bit of research to match its oddball tire size. Then the Sheldon Brown website came to my aid.

Great idea! I made a mess out of buying a new stem for a road bike and I can confirm that reading/guessing numbers from bikes parts is non trivial.

How are you going about monetizing this? Affiliate links?

Thank you! Yes, there are affiliate links on the page to get some money for the hosting, but that's not the main goal of the page.
I've never understood why bike manufacturers don't make it easier to look up parts by serial number. SRAM has done this right, you can search for parts based on s/n and it will give you exact specs (s/n is stamped onto the part). Their service manuals are also very well designed and free!
Nice website. Where did you source your data from?
Thank you! I used the official product specification from the manufacturers.
There don't appear to be any newlines. Wasn't it hard to edit by hand that way? (Unless I am missing something)
Are you looking into the HTML code? It's minified by the deployment script.

That's not the way I edit HTML files. :-)

May I ask what you’re doing in your deployment script?
The deployment script minimizes the text files, creates gz files for nginx, and copies the files to the webserver host.
The most useful link on HN of the year has already been posted. Those labels are baffling.
Thanks for this, I remember going down a rabbit hole parsing the codes on my last set of tyres trying to figure out what to replace it with (I learned there's a standard, ETRTO [1]) and I'm glad something like this now exists! Great work. Do you have plans for it beyond what's there already?

[1] https://en.wikipedia.org/wiki/European_Tyre_and_Rim_Technica...

Thank you! Right now, I just implemented my knowledge from my personal notes when I had to replace my tire. Maybe I'll add some more tools after I learnt something new about bikes.
Nit: Send me to the US version of Amazon if I'm from the US.
Good idea, I will think about that.
If you think decoding those numbers is tough, wait until you try fitting road (700c) tubeless tires. Buying is the easy part as in theory any 700c tubeless tire will fit provided you're within the appropriate width range, which is relatively generous (provided you respect hooked/hookless). In practice it is far more complicated and the experience can be a nightmare. Sometimes the wheel/tire manufacturers don't follow standards, other times they do but results leave something to be desired. You have Uniform Standard Tubeless, Tubeless Ready, Tubeless Easy, Tubeless Compatible, hooked, hookless, yet no real guarantees the tire and wheel will be compatible.

I fit Continental GP5000TL (depending on the generation and width, they are notoriously difficult to mount) to two different sets of wheels. One set of wheels gave me a hard time and it took 30-45m per tire, but they eventually went on. On the second set of wheels, one went on easy enough. The second took well over an hour and resulted in multiple blisters (and much cursing) even after using every known trick. Schwalbe Ones in comparison mounted in a minute with no struggle, and actually hold air better than the Contis which can supposedly be used without a sealant.

Did you try a tire bead jack? The Kool Stop one has worked wonders for me getting GPs on.
I figured someone would ask - no, I didn't have one handy, all LBSs were sold out and online orders would have taken too long.

Did I learn from the experience? Absolutely not, still haven't bought the Kool Stop jack ...

Did I break down and take it to the LBS for mounting? Also, absolutely not. Why pay someone $20 to mount the tire when I can spend an hour fighting it and end with nasty blisters?
I've heard quite a few people complain about GP5000TLs, but that's what I've been using for a while (on Prime carbon wheels) and haven't had too much trouble with them. With tubeless tyres, you really have to make use of the inner rim well (i.e. the middle bit) to give you the crucial extra mm or so. At least with tubeless tyres you can use tyre levers to get the last bit on and not worry about puncturing a tube. Schwalbe Ones are easier to fit in my experience, but they seem to have the durability of butterfly wings and even worse, they can get slippery in the wet when they're at high pressure (e.g. over 70psi).

I've seen videos of people easily fitting tyres using just their thumbs, but I refuse to believe that's possible.

It entirely depends on the rim. First generation GP5000TLs were impossible to fit on some rims, difficult to fit on most rims and reasonable on a few. Second generation (I think late 2020/early 2021) are a slightly looser and will fit on more rims. I can't speak about the latest gen. released late last year.

I personally love GP line of tires (used 4k/5k clincher and 5k TLs) as they have a good compromise of puncture protection, tread wear and rolling resistance. They generally rate at the top for just about any tire I'd use in a non-race scenario. I will not buy another pair though until I switch wheels as I have no desire to torture myself. I did not go as far as to bake the tires to loosen them, but I did let them sit out in the sun which made a bit of a difference.

The other factor to consider is roadside repairs. If you have a really hard time mounting the tire initially and you puncture severely enough to need a tube (sealant leaked and plug won't hold), you're likely calling for a ride back. I did find they loosen after 500-750km so you are more likely to be able to fix it roadside if needed. I sliced the sidewall on my almost new GP5k but thankfully the plug held. Irresponsibly I used it for another 500km+ until it would no longer hold pressure overnight, but I do not recommend that route!

As for using tire levers - buyer beware when it comes to carbon. I resorted to levers, but you do run a risk of permanently damaging your wheel. I have seen a picture of someone put one of the plastic with steel spine levers straight through their rim doing this. A tire bead jack is a far safer and far easier option (though I've yet to buy it).

It is really pissing me off that "tubeless ready" wheels and "tubeless ready" tires have made it infinitely harder to just fit a tire with a good old tube inside.
Can you elaborate on this?

With the exception of hookless rims (which are not common yet, at least here), TL wheels will take a clincher tire and tube, and TL tires will take a tube. The potential incompatibility comes from TL tires and TL wheels, not at all related to tubes, and is because of lack of spec and manufacturing tolerances.

normally when fitting a tire, you put the bead on one side in the "gutter" in the center of the rim where the diameter is narrower while you lever on the bead on the second side. leaving the first bead loose and un-seated while you pop on the second bead makes it pretty easy.

rims with thick rim tape designed to seal with tubeless tires have much less gutter, so it's a bit more difficult to squeeze the last bit of the tire onto the rim. they're compatible, just difficult to work with.

There are tire/wheel TL combos that are just not compatible, no matter what you try. Centering the tire is key, soapy water helps, you may need to warm up the tire, a tire jack may be needed in some cases .. but none of those will work 100% of the time, which is ridiculous.
Sure, except now rim and tire manufacturers go to the opposite ends of manufacturing tolerances on their respective parts because no one wants some niche road tubeless setup popping off at 7 bar. The result is tires like the GP5k (not even TL version) where I've struggled to get even the first side over, on rims that are tubeless ready and, no coincidence, have a history of being difficult to fit tires on.

I want to be able to fix a flat outside, not call an Uber.

Ah fully understand, I thought you meant there is somehow incompatibility between tubes and TL wheels/tires.

I’ll echo your frustration 100%. I found Schwalbe Ones are much looser fitting and have no problem mounting them on two sets of rims I have that will barely take a GP5K.

Indeed, there's one bike in the family fleet, a Surly with tubeless-ready 650b's, that are a beast to mount. I can get them on and off, but I have strong hands -- jazz double bassist for 40 years. My spouse has no hope. If she flats on a ride, she has to make the Call of Shame. ;-) This isn't reasonable.

As I read somewhere else, Frank Schwinn and Frank Brilando wanted a bike to be serviceable by a 10 year old.

I did okay with gp5000 clincher for tubes, and just two cheap plastic tire levers and my own thumbs. But what you have described for the tubeless version is something I've seen very widely reported from a number of other sources as well.
The first scenario in the FAQ sounds more like a pinch-flat to me. This happens when you ride up a curb or over a rock and the tire compresses, pinching the tube between the rim and the curb. Running higher tire pressures, using a product like CushCore, or as the author discovered running stiffer casings can all help reduce the incidence of pinch-flats.
A pinch flat (aka snake bite) will generally have two pinholes, making it relatively easy to identify.

With that said I have never had a flat on the outside of the casing without actually an obvious sidewall tear/puncture. Definitely possible, but I would say it is far less likely.

Thank you for the hint.
I'd also add an important point - never replace a punctured tube without thoroughly checking the inside of your tire for sharp objects. You'll likely only make this mistake once.
I've never really found a good way to check - visual check can miss things, running your hand around the inside works but you're liable to get something such in your hand! Wiping a around can work. But I've not come up with anything better? Maybe a tissue, or microfibre cloth will snag more easily and avoid missing something?
I am often still wearing my biking gloves anyways, so I run my hand around inside, and then toss them in the wash when I get home.
I take the chance and run my hand on the inside. Gloves should usually work well too, though I use fingerless on road.

For off-road riding (cross) I pinch flat almost exclusively so I don’t bother checking around. It is pretty obvious when you smack a root or rock.

This is really cool, thank you for sharing!

It would be neat if the information and links could be localized.

Thank you! The web page is in English and German for now.
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Great work and thanks for NOT making this an app. The people that creat the standard should have done this.
Huh. I thought the C in 700C indicated that the tire was a clincher as opposed to tubular but that seems to be wrong.

You tool says:

> Reifenhöhe C: ca. 39 mm (French designation)

but it says that for 700x19C as well as for 700x40C which seems odd?

The wikipedia page for Bicycle wheel [1] says:

> The ISO 5775-2 standard defines designations for bicycle rims. It distinguishes between 1. Straight-side (SS) rims 2. Crochet-type (C) rims (...)

and also

> Road wheels may be designed for tubular or clincher tires, commonly referred to as "700C" tires.

but it doesn't explain the B in 650B.

Sheldon Brown [2] says (emphasis added)

> A second number or letter code would indicate the *width* of the tire. (26 x 1.75, 27 x 1 1/4...650B, 700C...)

The wikipedia page does mention both 650B and 650C and that the ISO diameter differs by a few mm. So if I understand right, these codes (650B and 700C) specify the full-wheel diameter (650/700) and the letter indicates how much of that diameter the tire needs to make up, i.e. a 650B rim is slightly smaller (571mm) than a 650C (584mm) and the tire needs to make up that differencxe to get to 650?

[EDITED] 700C rims are ISO diameter 622mm, which matches with 2x 39mm tire width: 622 + 78 = 700mm. So I guess the intended tire height at time of standard-invention was 39mm?

But in practice a 700x19C rim-tire combo will be smaller in diameter than a 700x40C so I guess they're not fully "700C" standard compliant?

[1] https://en.wikipedia.org/wiki/Bicycle_wheel#650B_gravel_bicy...

[2] https://www.sheldonbrown.com/tire-sizing.html

Wow, thank you very much for the valuable information. I will check how to improve the page accordingly.
Pasted description below from Sheldon's page. The A/B/C designation is even more confusing when you consider 700C wheels/tires which these days range from the uncommon 19mm to well over 40mm.

In the French sizing system, tires are designated by a three-digit number, which may be followed by a letter. The number is the nominal outside diameter of the tire the rim was originally designed for. The absence of a letter indicated a narrow tire; "A", "B" and "C" indicated increasingly wider tires."A" was originally a tire about 30 mm wide, so the 650A rim is pretty large, 590 mm. If you add the top and bottom 30 mm tire thickness to 590, you wind up with the 650 mm tire diameter.

The 650C size was originally intended for a quite wide tire, about 40 mm wide. Top and bottom 40 mm tire plus the 571 mm rim size again bring you to a 650 mm outside diameter, even though the rim was smaller.

Interesting historic context!

My understanding is that in the current world the suffix doesn't really matter, since all 28" rims and tires are marketed seem to be marketed as 700c, and all 27.5" ones as 650b. The height of the tire pretty much correlates with the tire width, so one would rather look at the tire and rim width to determine whether they are compatible (wider rims should be used for wider tires).

And it's actually fun that 700c bikes are usally ridden with narrower and lower tires than 650b bikes (which was in the recent years mostly used for mountain bikes and tire width of >= 2.3"), despite this designation claiming the opposite.

Actually 650b is used when the tire width is less than 50 mm (randonneur and gravel bikes) and 27.5" when the width is over 50 mm (mountain bikes). Jan Heine and Kirk Pacenti reintroduced this size.
In the mountain bike world, there's really only two modern standards - 650b (also called 27.5in) and 29er's. 26er's were a thing for the longest time, but really no one makes new bikes in that size anymore.

We're mostly riding on wider tires, 2.3 seems to be a rational minimum for real trail riding, and you'll often see widths of 2.6 and beyond (and fat bikes of course go way wider) on both 27.5 and 29in bikes.

Needs a note re tubeless setup, esp for mountain bikes. Fewer punctures, easier to repair in the field. Tubeless-ready tires should also have a note on the sidewall.
Thank you for the hint!