Help - rim/tyre sizing advice needed please!

[phantasmagoriana]

I've just taken the wheels off my hybrid (outside in the snow  ) ready to fit my studded tyres. However, I've found a bit of a problem - the rear rim is only 16mm, and the tyres are 700x38. (I'd looked at the front rim, which is 18mm, and assumed that they were the same size - of course that would be far too easy...).

Sheldon Brown's chart suggests that this tyre would be too wide for the rim - would it be a bad idea to even try fitting it? 

If so, I do have another pair of wheels which might work (19mm rims), but the rear axle is slightly too wide for this frame (135mm rather than 130mm). However, I suspect it might be possible to get the wheel in there with a bit of effort (it's a Reynolds 501 frame). It's also got a 6 speed freewheel rather than 7, which I realise is going to mess up shifting, but I could always pretend it's a singlespeed as my commute is pretty flat - staying upright is the main priority!

Any advice greatly appreciated...

 

[e-rider]

but what about 17mm mtb rims that take 2.4 inch tyres!

it's all about the bead seat diameter, and frame clearance.

I think you'll be fine.

 

[P.H]

Sheldon also says;

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

On his chart 15mm is good for up to 32mm and 17mm is up to 37mm.  So 16mm and 38mm is'nt that far off.  As you already have them I'd fit and see what they feel like, you're not going to be over inflating these which I would imagine is the main reason for the caution on the chart.

 

[phantasmagoriana]

Thanks for the reassurance - I think I'll give them a go. I also found Schwalbe's own chart and it suggests a 17mm rim can take a 50mm tyre, so hopefully 1mm narrower with a 12mm narrower tyre won't cause problems! 

 

[bobg]

This is very helpful to me too but just to clarify, are all your reference to 17mm 19mm rims etc related to the width between the horns of the rim??

 

[HJ]

Instructions on measuring rim width here and advice on which tyre width fits which rim width here. Hope that helps.