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Wheel size and luggage advice please!

by Crashboy
Sat, Sep 03, 2016 19:36
4

Can anybody shine light on / point me in the direction of info about the following:

 

I have a Marin Four Corners - small -  which is awesome and I love it very much.  It says on the Marin website it will accomodate 700 x 45 or 29 x 2.1.

 

My question is:  in terms of equivalence, does this mean I can fit 27.5 x 2.1 (or wider) too? Do we think it will drop the BB too much resulting in pedal strikes or make the handling too wrong?

 

Am thinking of chunkiest poss for winter bridleways you see...

Also, (same bike, not necessarily same time!) luggage - front rack only (as seems to be creeping in popularity) or a trad rear pannier setup for commuting / shopping?

 

Thanks all....

If you're new please join in and if you have questions pop them below and the forum regulars will answer as best we can.

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4 comments

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Crashboy | 8 years ago
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...all very interesting, thanks guys for input so far.

 I think - upon mulling it over  - if the frame is designed for 29er wheels and up to 2.1 tyres, I suppose the frame itself won't take the kind of terrain you might be tempted to ride over on more cushy / knobbly tyres?

 

Mind you, Having seen the new Genesis bikes article on here I really love those gum wall kenda small block eights on the Vagabond...and they are 29x2.1.......if I can source a pair of those I could forget my wheel size fixation!!

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DaveE128 | 8 years ago
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But 700c x 45 as per the OP is 712. This gives 10.5mm difference not 6.5mm doesn't it?

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DaveE128 | 8 years ago
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If my reading of http://www.bikecalc.com/wheel_size_math is correct, your BB would drop about 11mm, plus any difference due to reduced tyre pressure.

I think that would probably be ok if you don't pedal round sharp corners and you're careful riding over any technical stuff. The impact on gear ratios will probably be noticeable - you'll go 9cm less distance for each wheel revolution, so the gearing would be 4% lower.

If you can fit wider tyres it would reduce this difference slightly, but again, depends on tyre pressures.

Whether you can fit wider 27.5 tyres depends on the shape of the frame at the front of the chainstays and the seatstays around the tyres, but I suspect you'll have problems with tyre width as much as the diameter.

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Crashboy | 8 years ago
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Many thanks for the comprehensive reply.

My worry / confusion is the whole  equivalency thing regarding diameter of a bigger rim / smaller tyre vs a smaller rim / bigger tyre....

The bit about ratios is very interesting, (although I'm not sure I ever acheive those kinds of RPM / speeds anyway!!) and I hadn't considered any impact on the speed TBH.

 

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