too wide tires for small rims?

derfurz65
derfurz65 Posts: 4
in Workshop
So i've been riding 28c tires on my roadbike for some time and a friend of mine is still rocking old 23c on 13c rims(to my knowledge/ Rigida 18 from the 90s)on his roadbike. His tires a bassically toast now and ,as he, liking the more comfortable 28c on my bike, could get left-over 28s from a friend for free, we were wondering if they would fit the rim. Brake and frame clearance is not a problem, but to my knowldege 13c rims, if they are, are only supposed to fit up to 25C. The question I have now is, if anybody has actually tried this setup and if it really does make alot of difference, as I think 15c rims can fit up to 33c tires. I just wanted to ask if anybody actually has got experience with this before going on a trip and noticing some long way from home that it just doesnt work.

Comments

  • ugo.santalucia
    ugo.santalucia Posts: 28,321
    I seem to recall the Rigida Chrina (similar to yours) don't take 28 mm tyres... they just pop, which is quite dangerous
    left the forum March 2023
  • step83
    step83 Posts: 4,170
    Agree with Ugo, I wouldnt try it, Mavic do a rough guide which I can't see any problems with. safe minimum is 15c but thats still going to be sketchy and feel weird in corners


    Titanium Px Spitfire
    Easty commuter
    Tripster AT
  • Charlie_Croker
    Charlie_Croker Posts: 1,727
    edited January 2020
    It depends on the chart you look at as far as i can see. I also guess the tyre pressure used has an impact. Shame there is no independent test data available, maybe there is but I can't find it ATM. I'm having a similar dilemma with some Ambrosio 622-14's on my Bianchi, I'd like to try 28mm but... is it safe?
    If anybody can supply a link to test data, I'd be very interested to read it




    Source:https://www.wtb.com/pages/tire-rim-fit-chart

    .
  • ugo.santalucia
    ugo.santalucia Posts: 28,321
    Charlie_Croker said:

    It depends on the chart you look at as far as i can see. I also guess the tyre pressure used has an impact. Shame there is no independent test data available, maybe there is but I can't find it ATM. I'm having a similar dilemma with some Ambrosio 622-14's on my Bianchi, I'd like to try 28mm but... is it safe?
    If anybody can supply a link to test data, I'd be very interested to read it




    Source:https://www.wtb.com/pages/tire-rim-fit-chart

    .

    Never had any issue with Ambrosio Excellence/Evolution and 28 mm tyres
    left the forum March 2023
  • Charlie_Croker
    Charlie_Croker Posts: 1,727
    ugo.santalucia said:

    Never had any issue with Ambrosio Excellence/Evolution and 28 mm tyres

    That's good to know.
    Also, I’ve been down my LBS this evening and I asked the owner for his advice as he’s been in the bicycle business for a lot of years now. He reckons provided the tyres actually fit within the frame/forks I won’t have any problems with regard to them coming off the rims. So unless somebody can prove this is an error I’m gonna give it a go - if I do encounter any difficulties, I’ll be sure to re-find this thread and post back
  • derfurz65
    derfurz65 Posts: 4
    ugo.santalucia said:

    I seem to recall the Rigida Chrina (similar to yours) don't take 28 mm tyres... they just pop, which is quite dangerous

    First of all thank you all for the input.
    Not questioing it but any idea why that would be? If I see some mountain bikes with their tire to rim ratio I was asking myself how one could fuck up a rim design so that it wont hold a wider tire, even if that would mean, as stated above, that it feels horid to steer.
  • ugo.santalucia
    ugo.santalucia Posts: 28,321
    derfurz65 said:

    ugo.santalucia said:

    I seem to recall the Rigida Chrina (similar to yours) don't take 28 mm tyres... they just pop, which is quite dangerous

    First of all thank you all for the input.
    Not questioing it but any idea why that would be? If I see some mountain bikes with their tire to rim ratio I was asking myself how one could censored up a rim design so that it wont hold a wider tire, even if that would mean, as stated above, that it feels horid to steer.
    Partly anecdotal... in the sense that it has happened to a few people and partly because Chrina are particularly narrow... similar rims of the same period are either 14 or 15 mm.

    They were designed in a time when 23 mm was considered a wide tyre and there were no 28 mm road tyres on the market.
    Bear in mind 21 mm tyres were the norm and 19 wasn't unheard of
    left the forum March 2023
  • thecycleclinic
    thecycleclinic Posts: 395
    It also depends on the tyre. I had 27mm Vittoria paves on 13.4mm I ternal width rims once. They did jot feel like paves should. On a wider rim they felt great.

    Wide tyres on narrow rims dont feel right. It is not necessarily unsafe.

    13mm internal width is for 25mm max but they are better with 23mm tyres.

    Mtb tyres have stiffer sidewalls so you can put a wide tyre on a narrow rim in this case. The tyre shape is still wrong but its safe.
    www.thecycleclinic.co.uk
  • Charlie_Croker
    Charlie_Croker Posts: 1,727
    I’d go further and say it depends on both the tyre and the rim combination. I know from riding a motorcycle, putting a wider (narrower profile) tyre on a narrow rim doesn’t give the same footprint or feel as on a modern wider rim. But having said that, you have what you have and without changing everything, trying a different tyre is the easiest/cheapest option.




    You can see from this how the contact area (footprint) can be affected, though it must be said cycle tyres tend to run at higher pressures so the effect is perhaps little less extreme than shown here
  • svetty
    svetty Posts: 1,904
    Why risk it for the sake of a few quid? Having the front tyre part with the rim at 40mph downhill isn't going to end well......
    FFS! Harden up and grow a pair :D

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