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Tyre sizes – can I have 28c front and 25c rear

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  • March 24, 2020 at 6:13 am #30570
    danfitzjohn

    Hi all,

    I have discovered that my BMC GF 01 wont take a 28c tyre (due to the frame)

    Has anyone got any experience with having 28c in the front with 25c in the rear ? Would there be any advantage / disadvantage of doing that?

    Thanks in advance!

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Viewing 11 replies - 1 through 11 (of 11 total)
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  • April 3, 2020 at 5:03 pm #956969
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    LastBoyScout

    Was also the case pre-front

    Was also the case pre-front suspension to run a bigger tyre at the front for more cushioning.

    I used to run a 2.1″ Panaracer Smoke Dart front and a 1.8″ Smoke Lite rear on my old MTB – ah, the nostalgia…

    April 3, 2020 at 9:57 am #956967
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    Yorkshie Whippet

    Absolutely nothing wrong with

    Absolutely nothing wrong with 28f and 25r, over the last 20 or so years I’ve set up every bike I’ve had with a larger front tyre at some point. This set up is my current default.

    As pointed out elsewhere it is almost default to set up mtbs as such.

    March 26, 2020 at 8:18 pm #956965
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    lio

    Conti 5Ks are actually peetty

    Conti 5Ks are actually peetty accurate size  wise. 4Ks on the other hand are definitely “big” tyres.

    A 25mm Conti GP is close to 27mm on a C17 rim.

    March 26, 2020 at 1:43 pm #956963
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    peted76

    I run 23F/25R never heard of

    I run 23F/25R never heard of anyone running a larger front tyre. 

    I would imagine that getting the PSI right each time you pump up might take a bit of getting used to.

    I can’t think an one advantage to running a larger ‘front’ tyre… remember 60% of your distributed weight will be on the rear wheel… It sounds to me like you might be stuck with 25’s…. 

    However you can get ‘large’ 25’s.. I think the new Conti5000’s are one of if not the largest 25’s on the market.. so it might blow up to 27 or 28mm tyre depending on your rim. 

     

    March 26, 2020 at 12:12 pm #956961
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    Chris Harris

    Same here, my logic being a

    Same here, my logic being a larger tire for a little more comfort rear, smaller tire for better aero match to the rim at the front. Seems to work for me. Never heard of anyone doing the reverse.

    March 25, 2020 at 11:50 am #956959
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    IanEdward

    Not unusual to run a wider

    Not unusual to run a wider tyre on the front of MTBs, that’s where you need the most grip. Same applies with road bikes, I’ve ridden out of back wheel slides but never ridden out of a front wheel slide. Wider front would help prevent the front washing out.

    March 25, 2020 at 11:43 am #956957
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    bobbinogs

    You don’t need to contact the

    You don’t need to contact the manufacturer.  The only issues you could possibly have are that 28s are too wide/narrow for the rim, but that is unlikely.  Just check the rims for the ETRTO/ISO number.  They will probably be 622-xx, where 622 indicates the bead seat for a standard 700c wheel and xx is the internal rim width.  Hence, 622-15 or 622-17 is likely in your case, both of which will suit 25 or 28mm tyres.  There are quite a few guides around on what will work with what. 

    Key point though is that there is little to gain from running 28f and 25r (as stated, a better combo would be 25f/28r) but give it a go if you want to and see what you think.

    March 25, 2020 at 10:59 am #956955
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    Richard_pics

    Ive run the opposite with

    Ive run the opposite with zero issues, 25 front, 28 rear.

     

    March 24, 2020 at 8:20 pm #956953
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    danfitzjohn

    Thanks everyone, good point

    Thanks everyone, good point and I’ll contact the rim manufacturer to see what they say..

    March 24, 2020 at 6:46 pm #956951
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    Jack Sexty

    I had the opposite on a

    I had the opposite on a discontinued 13 (Halfords own) road bike and ran a 28 rear and 25 front with no issues for a while until I sourced a replacement 25. I may ask a tyre and/or wheel manufacturer what their official stance is, because I’m genuinely interested what they have to say more than anything. 

    March 24, 2020 at 11:24 am #956949
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    bobbinogs

    No problem with mixing tyre

    No problem with mixing tyre sizes as long as the rims are fine with that.  I know a few people who want to ride 28s but cannot due to frame clearance, so often end up with a 28/25 combo.  Thing is though, one of the main benefits from going 28 (providing one drops pressure accordingly) is to improve comfort and the biggest bang for the buck is always the rear.  There are some very marginal aero gains to be had going 28 on the front providing the rim is built for that.  In most cases, riding 25 on the front is about right and buying tyres in pairs can be cheaper…

    TLDR?  Don’t bother unless you are getting sore hands due to excess vibration.

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