Tyre advice needed

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cbgb

New Member
I bought a Specialized Sirrus Elite 2009 which came with 700 x 28 tyres which was thinner than my normal commute on a Scott Sportster with 700 x 35 tyres (marathons upgrade). My commute is a mix of road, towpath and cycle path and as a result the Specialized struggled and i suffered loads of punctures so it went away and the Scott came back out.

Then i had a bright idea..... I put the 700 x 35 tyres on the Specialized Sirrus and started using it again. I have now been using it for about 3 weeks and its been great with the Marathons 700 x 35 fitted. Its like a new bike and i feel its up to the job again.

Then today when i left work i got on my bike started to ride and noticed that i had a puncture on the front? The tyre popped out of the rim and wedged the front break locking the wheel. Fortunately i had only just started so i was not travelling fast enough to cause me a problem. I dread to think what would have happened if i was flying down a fast section of the ride home as the front could have locked and thrown me over the handle bars (possibly into traffic?). I fixed the puncture and rode home slowly in fear that if i did get a puncture i would be facing certain death?

The question is.. Should the Specialized Sirrus which came with 700 x 28 tyres be able to accommodate 700 x 35 tyre?
Was it the size of the tyre which caused the locking of the front wheel or is the tyre popping out the rim just as likely with the 700 x 28 tyre?

I dont realy want to ride it on 1 700 x 28 as the ride is rough and i get to many punctures. Its a great ride with the 700 x 35.

And if anyone is thinking just ride the Scott to work with the fatter tyres the answer would be, i would but i have ragged the arse of it over the last few years and done thousands of miles on it. Its used now as my second bike. I got the Sirrus for good price so may as well use it for the commute to work.
 

Gerry Attrick

Lincolnshire Mountain Rescue Consultant
It depends on the width of the rims. There is a safe limit to the width of tyre a given rim width will take. Peruse this for in depth information, specifically the heading "Width Considerations".
 
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cbgb

New Member
It depends on the width of the rims. There is a safe limit to the width of tyre a given rim width will take. Peruse this for in depth information, specifically the heading "Width Considerations".

Thanks for your help guys.

I have just had a look at the different rims and the Sirrus has 622 x 14 ( 700 x 28 tyre) and the Scott has 622 x 17 (700 x 35 tyre). Apologies but i dont quite understand the Sheldon Brown Chart? should i be looking at the 28 and 35 on top row & 14 and 17 on side. If so then the Sirrus rim 622x14 would only accept 700 x 20 , 700 x 23, 700 x 25, 700 x 28 tyre and not the 700 x 35. Is that correct?
 
You're rim width is 14mm (its only 13 or 15 on the chart but hey ho) reading along the 15mm row your wheel will accept tyres between (and including 23mm and 32mm). Hence a 700x32 is what Sheldon would recommend.

Seperately, Ive just remembered, the rim on my old 37mm shod hybrid failed and I borrowed my old sirrus wheel it didn't even last a week before it too failed! A bit late but the day after I read about Sheldons chart :-(
 
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cbgb

New Member
Thanks for all the help. I think a new set of Marathons are going to be in order (better safe than sorry) . The 35's can go back on the Scott.
 
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cbgb

New Member
perhaps you could swap the wheels over from your old bike?

Nice idea but the rear rim on the old bike almost needs replacing due to wear
 

Alembicbassman

Confused.com
I swapped my skinny 700x28 slicks for a set of Schwalbe Marathon 700x28.

The treaded Schwalbe are much thicker than slick 700x28, I had to adjust my mudguards up another 5mm to get them to fit over the tyres.

They also have a kevlar belt to guard against punctures.

I paid £10 each at Planet X for the standard Marathons.
 
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