Inner Tubes for Conti Grand Prix 4 Season 28mm

by ladeside09   February 4, 2013  

guys, apologies in advance for the dumb post...but

looking to buy 28mm Conti gp 4season tires for my road bike....

my current tubes are Conti 18-25c - I personally reckon I would need new tubes but some feedback on various forums suggest I can get away with using my current tubes-

Is this the case or what would be the more suitable of the 2 options below?

Schwalbe Inner road 18-28c tubes
OR
Continental Tour 28 slim tubes 28-37c

any feedback welcome
cheers

8 user comments

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Conti 28 mm tyres actually measure 25 mm. I use Conti 18-25 in my 28 mm Conti GP 4 Season, no problems.

two wheels good; four wheels bad

posted by cat1commuter [1321 posts]
4th February 2013 - 15:12

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Your current tubes that are marked 18-25c will be fine, the upper limit is nominal. By putting a 25c tube inside a 28mm tyre it only means the tube is fractionally more stretched than it would be otherwise and well within its limits.

In the case of a tyre that comes up smaller than spec, as it seems with the GP4Season, then it's even less of an issue.

You may be more likely to get pinch punctures with a larger tube.

Simon E's picture

posted by Simon E [1885 posts]
5th February 2013 - 11:31

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Thanks lads for your feedback, I.'ll stick with my current ones
Cheers

posted by ladeside09 [9 posts]
5th February 2013 - 12:42

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Simon E wrote:
Your current tubes that are marked 18-25c will be fine, the upper limit is nominal. By putting a 25c tube inside a 28mm tyre it only means the tube is fractionally more stretched than it would be otherwise and well within its limits.

In the case of a tyre that comes up smaller than spec, as it seems with the GP4Season, then it's even less of an issue.

You may be more likely to get pinch punctures with a larger tube.

Bigger tubes can be a pain to get into the tyre and can puncture as you install them too.

Ah! Condor

posted by Bedfordshire Clanger [307 posts]
5th February 2013 - 14:56

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Guys, had a job fitting the tyres on the rim then one of the inner tubes is now flat,
My Rims are 13mm - should this be alright for the conti 4s 28mm or
should I have opted for the 25mm?

My brakes are 57mm deep drop so clearance that way is not an issue
Again any feedback welcome
Cheers

posted by ladeside09 [9 posts]
9th February 2013 - 20:37

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I don't think your rims are too small, some tyre+rim combinations are tighter than others.

You may have caused a pinch puncture in the tube as you fitted it. Check the tube and valve and refit carefully. Try to keep the bead of the tyre in the well of the rim, as shown in this video from Spa Cycles.

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posted by Simon E [1885 posts]
10th February 2013 - 21:03

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Also check where the valve connects to the tube, I've had 2 conti tubes where the valve has come away from the tube last weekend.

posted by bigant [39 posts]
19th February 2013 - 4:45

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Rim will be fine for 28 mm tyre (particularly since the tyres actually measure smaller than 28 mm).

Did you have the tube partially inflated while fitting it? This helps prevent pinching it between the tyre and the rim when levering the tyre on.

two wheels good; four wheels bad

posted by cat1commuter [1321 posts]
19th February 2013 - 18:15

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