Fat tyres (700 x 42c) - can I go any smaller?

[joolsybools]

Hi,

I have recently bought a Specialized Globe Comp which has 700 x 42c tyres - I would like to go to a slimmer tyre but am not really sure how thin I can go. I've looked at Sheldon Brown but not sure my size was on there.

Here's a link to my bike's spec - it says the rims are Specialized Globe, 700c, 32h, double wall w/ machine sidewalls and eyelets if that helps. I'd ideally like to go to a size where I can easily fit Schwalbe Marathons and some mud guards :0)


Thanks in advance

http://www.specialized.com/gb/gb/bikes/archive/2007/globe/globecompwomens#specs

 

[Andy_R]

You really need to measure the rim inner width as discussed on sheldon's page about tyre sizing. Without that measurement, it's pure guess work.

 

[joolsybools]

Thanks, I put the wrong link up before, here is the correct one, not that it will change your advice I am sure! http://www.specialized.com/gb/gb/bikes/archive/2007/globe/globecompig8womens#specs

 

[Pauluk]

Most hybrids and some MTBs have 17mm to 18mm rims which means you can safely go down to 28mm tyres but as Andy_R says you should really measure your internal rims first. If you don't have anything to measure this your LBS should be able to do it for you. Just deflate the tyre, measure the internal rim and reinflate.

 

[joolsybools]

Sounds like a job for the weekend, cheers!

 

[GrumpyGregry]

read what sheldon says at the bottom of the table


"Note: This chart may err a bit on the side of caution. Many cyclists exceed the recommended widths with no problem."

You should have little problem coming down a few sizes provided you keep your tyre pressure up but then you may find it gets uncomfortable,

also iirc that bike may have a carbon fork and may not have fittings for a front mudguard. Doesn't mean you can't fit one but it might be worth getting some hands on advice from a decent local bike shop.

 

[mcshroom]

I'd bet on there being either 17mm or 19mm rims on that bike. Either would let you go down to 28mm easily enough. I'd recommend 32mm as a nice compromise tyre width.

 

[Cyclist33]

Thanks, I put the wrong link up before, here is the correct one, not that it will change your advice I am sure! http://www.specialized.com/gb/gb/bikes/archive/2007/globe/globecompig8womens#specs

Take the tyres off, get a ruler and measure the width from one side of the inside of the rim to the other. Eg my hybrid's are 14 mm. After that, people here will advise you what suitable range of tyre widths apply.

As mcshroom suggests, 32mm sounds like a reasonable compromise between pace, comfort and traction, and it would be surprising if they didn't fit your Globe's wheels.

Stu

 

[ArDee]

The great Sheldon recommends a Tyre width of 1.4 to 1.8 times the width between the inside dimensions of the rim.

 

[GrumpyGregry]

The great Sheldon recommends a Tyre width of 1.4 to 1.8 times the width between the inside dimensions of the rim.

Thus demonstrating his views, if they are his views, are simply subjective guidance.

 

[MrJamie]

I'd be curious what surfaces you ride on too. I switched my hybrid from 700*40 knobbly Kendas to 700*38 Marathon Plus and while its a tiny bit better for the road its a lot less grippy on trails/tracks, im probably going to switch to something like thes for winter http://www.bike-discount.de/shop/a12469/marathon-plus-tour-28-42-622-reflex.html?lg=en&cr=GBP&cn=gb

 

[joolsybools]

Hi everyone, I finally got around to doing this today and my rims are 17mm as mcsroom suggested, well my back one is so I am assuming my front one is too. So according to Sheldon http://sheldonbrown.com/tire-sizing.html I could go down to anything between 25 and 37. I agree 32 sounds like a good bet then. I will probably just do the rear tyre for now as finances are tight atm. The tube I have in is a 700 x 45C so I will need to 'upgrade' that too!

In the end I managed to get hold of some SKS Blakc Chromoplastic mudguards, they were an absolute swine to fit!

Mr Jamie I mainly ride on road, cycle paths and occasionally a bit rougher terrain.

Thanks to everyone who helped on this thread

 

[citybabe]

I had huge knobbly 700*40 tyres on a cheap second hand hybrid I once picked up. My LBS said I should be able to go down to 28's with no problem. I replaced them with a couple of Schwalbe Sport tyres but the inner tube kept coming out from under the tyre. I took the tyres off again but tbh I've not used the bike since.
It could be that the rims were poor quality and not holding the tyre in place