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Second set of wheels for trails

dUNCdUNC Posts: 73
edited March 2009 in Workshop
Apologies for potentially putting this in the wrong place and for cross posting (had this in the Commuting Workshop with no replies).

I've got a hybrid (Specialized Sirrus) running with 23mm Stelvio Plus tyres for my road commute to work. My missus is wanting a MTB for her birthday so we can start going out, but she's only interested in pootling along paths and trails (and all on the flat :) ).

Obviously I'm not going anywhere near those with my totally slick and skinny tyres and with no room for another bike I'm looking at getting a second set of wheels to put more appropriate tyres on to go on jaunts with her.

Even better, it's a chance to upgrade my wheels to something better (thinking like Fulcrum 7s) and use my old rims for the trail.

Now, how do I go about finding out what size tyres my rims will fit, and is there a scientific way to make sure I've got sufficient clearance for some chubbies? I think the bike originally came with 26mm (or maybe even 28mm) Armadillos if that helps.

Also, any other things I need to consider? Just struck me that obviously I need a new cassette too - does it have to be an identical one? I imagine it does in that it will need to be 9 speed, but do I need the same number of teeth on the sprockets? And will the indexing be out switching between two different casettes? I guess the brakes will need adjusting too...

So I suppose basically the question is: how much of a ballache is it really to have two different sets of wheels that I interchange?! :D

Thanks in advance for any help.

Posts

  • MrChuckMrChuck Posts: 1,663
    Assuming you have the clearance for fatter tires, the problem that springs to mind is different wear on the two cassettes and subsequent problems with how well the chain works on them.

    So, if you do 90% of your riding with one set of wheels, over time the cassette and chain will wear together. When you swap in your 2nd set the chain won't work very well with the relatively unused cassette.

    In reality this might not be such a big problem but it's maybe something to be aware of. I think you could use different sized cogs too as long as your rear mech could accommodate them- shifting should work OK, you would need to stick with the same number of cogs though.
  • maddog 2maddog 2 Posts: 8,114
    28mm will fit, and 32mm CX knobblies should also fit okay. The Sirrus has plenty of clearance, the only issue is the fitting the tyre on the rim okay. Remember CX bikes run rims like Open Pros with 32mm knobblies without fuss.

    What MrChuck said is also relevant - you need to match the cassette wear bewteen the wheels, to avoid disparities between chains and sprockets, which could cause the shifting to deteriorate. In practice it's pretty easy to do. I run winter wheels and summer wheels without problems, sometimes with different cassettes, sometimes I use the same cassette for both.
    Facts are meaningless, you can use facts to prove anything that's remotely true! - Homer
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