700 x 25C tyre height

member054
Posts: 36
Joined: Tue Jan 10, 2012 12:52 pm

700 x 25C tyre height

Postby member054 » Fri Sep 15, 2017 3:17 pm

Hello,

I bought some 700 x 28C clincher tyres (Continental Grand Prix 4000 S II) and have sadly found the frame isn't large enough to accept them. Before I buy 700 x 25C tyres, it'd be great if I could get some expectation of how big they are.

Does anyone have figures or can measure their 25C tyre? I'm looking to identify the tyre height from top of rim to the tyre contact point. Width is fine...

Alternatively if anyone lives in the west Brisbane Centenary area and can lend me a 700 x 25C tyre to test with, it'd be appreciated :)

Mububban
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Re: 700 x 25C tyre height

Postby Mububban » Fri Sep 15, 2017 3:43 pm

What bike are you using them on?

Were you using 23mm before? I'm not sure if 25mm would be exactly in between the 23 and 28 with the different ways brands measure up.
When you are driving your car, you are not stuck IN traffic - you ARE the traffic!!!

member054
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Joined: Tue Jan 10, 2012 12:52 pm

Re: 700 x 25C tyre height

Postby member054 » Fri Sep 15, 2017 4:01 pm

Mububban: It's a late-90s Colnago frame with Precisa fork - some research indicates the fork length is 1cm shorter than most (reference in this post: http://www.bikeforums.net/classic-vinta ... match.html). I bought the frame & forks on their own, so this is the first time I've put wheels in it...

uart
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Location: Newcastle

Re: 700 x 25C tyre height

Postby uart » Fri Sep 15, 2017 5:57 pm

member054 wrote:Hello,

I bought some 700 x 28C clincher tyres (Continental Grand Prix 4000 S II) and have sadly found the frame isn't large enough to accept them. Before I buy 700 x 25C tyres, it'd be great if I could get some expectation of how big they are.

Does anyone have figures or can measure their 25C tyre? I'm looking to identify the tyre height from top of rim to the tyre contact point. Width is fine...:)


It might vary a little bit depending on the width of the rim on which it is mounted, but last time I measured I believe it was pretty close to 26mm width and 24mm height for the conti's

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biker jk
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Re: 700 x 25C tyre height

Postby biker jk » Fri Sep 15, 2017 6:18 pm

On a 17c internal width rim a 25c Conti 4k is 25mm tall and a 28c is 29mm tall. This tyre measures very wide for its nominal size and I would choose a different tyre if it's a tight fit.

member054
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Joined: Tue Jan 10, 2012 12:52 pm

Re: 700 x 25C tyre height

Postby member054 » Fri Sep 15, 2017 6:38 pm

Thanks guys - the rims are 17c internal so I've got some information to work with.

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open roader
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Re: 700 x 25C tyre height

Postby open roader » Fri Sep 15, 2017 7:42 pm

Hi member054, I got your message and tried to reply but you need to change your message settings to accept message replies.

Cheers.

Matthew.
3rd class cycling is always better than 1st class walking

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Duck!
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Re: 700 x 25C tyre height

Postby Duck! » Fri Sep 15, 2017 8:21 pm

It's very dependent on the individual model of tyre. As per the example above, the GP4000s are on the big side for their stated width, both in actual width and in height. You can also find that softer compound, racier tyres will often have a taller profile than harder "training" tyres, because the tread belt is built up more to give some semblence of lifespan to counter the faster wear of the soft compound.
I had a thought, but it got run over as it crossed my mind.

member054
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Joined: Tue Jan 10, 2012 12:52 pm

Re: 700 x 25C tyre height

Postby member054 » Sat Sep 16, 2017 2:49 pm

An update... I've been reading more and this looks a common issue, so that's some peace of mind. I've measured between rim and fork and have ~26mm available and so the brain says to get 23C to play it safe.

Image

I found a chart of Schwalbe tyres measured height (http://biketouringnews.com/wp-content/u ... /width.jpg) and thought it was a great resource - I'd love to find charts for some other big brands, of course it's still best effort information and to be taken lightly.

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