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Confused about tyre widths on wheels! Please help!

by madindehead
Thu, Aug 20, 2015 13:20
7

Hello,

I am slightly confused about what tyres I can and cannot use on my wheels.

I have Fulcrum Racing 5 wheels (I think, as the bike came with them, but they are named Fulcrum S5 in the bike spec).

These have a rim width of 18mm (from the spec sheet: http://www.fulcrumwheels.com/system/documents/files/RACING_5_EN_03_2013....)

The wheels currently have 23mm tyres on them. If I have the clearance, what tyre sizes would be capable of being run without danger?

24mm? 25mm? 26mm? 27mm? 28mm? Are all of these sizes safe to use on these rims?

Thanks

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7 comments

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mrmo | 9 years ago
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I would actually suggest not changing the wheels yet, trash them through the winter then get something nice in the spring. No point ruining a new set of wheels by fitting them just before the shitty weather begins.

Avatar
Must be Mad | 9 years ago
0 likes

try www.superstarcomponents.com

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madindehead | 9 years ago
0 likes

No apologies needed.

Cool, I will make that a priority to replace them! Is there anything that people recommend? Are some good custom made wheels for all round riding good? I'm aiming to weigh around 60-65kg when I buy the new wheels, so that might influence the purchase!

Avatar
dottigirl | 9 years ago
0 likes

Sorry for the late reply, but I'm 99% sure the wheels are 5.5s, which aren't true Fulcrum 5s, they are a bastard OE mix of 5s, 7s and some other cr*ppy freehub. They don't last terribly long either, I managed to wear a rear out before I needed to replace the 4000s II I'd put on them.

I'd go 25mm with your Tarmac. Any larger and the lightbulb effect will affect your cornering.

And get some new wheels at your earliest convenience.

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jollygoodvelo | 9 years ago
0 likes

Basically you can use any 700c tyre that you've got clearance for. If you had unlimited clearance, huge sizes might lead to a 'lightbulb' profile which would give unpredictable cornering (imagine a beach ball balanced on a teacup - it'd just roll off).

There's a Sheldon Brown guide here http://www.sheldonbrown.com/tire-sizing.html#width but I'm not sure I'd take it as gospel. I run 25c Vittoria Pro Tech tyres on 622x19 CX rims with no problem.

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madindehead | 9 years ago
0 likes

Cool.

So, the only thing holding me back is how much tyre clearance I have on my bike. Which given it's a Tarmac Elite isn't much 2 (Will probably struggle to do 28 tyres)

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madindehead | 9 years ago
0 likes

Sorry, to add an update:

The spec sheet says the rim width is 18mm, but the rim size is specced as 700C(622x15C)

Both this Schwalbe link (http://www.schwalbetires.com/tech_info/tire_dimensions) and slowtwitch below seem to state that 15C can support 23, 25, 28 and 32 tyres.

http://www.slowtwitch.com/Tech/Implications_of_Rim_Width_2803.html

Just looking for some clarifiction really that I've worked it out correctly!

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