what do you need for an extra wheelset?

Ok, I'm pretty much a newbie - I have an old road bike with 700c x 25 tires, a 52-42 double crank, drop handlebars and downtube shifters, and just got a new flat bar hybrid with 700c x 35 tires and a 48-38-28 triple. I like the wide tires for balance and such when pulling the kiddies, and love the triple on the hills, but the new bike feels SLOW compared to the old. Would my hybrid feel much faster with 700 x 25s? If so, can I just use my old wheels (or find some cheap ones elsewhere if I decide to keep the roadie intact)? How would I make it compatible with the new hybrid's deraileur? Put on the same kind of rear cassette as the new bike has? I'm guessing that means a new hub that is for a cassette rather than a freewheel, yes? Are there brake compatibility issues? Should I bother? Maybe I should just upgrade the other parts of the old roadie.

Sigh. My bike maintenance class was cancelled b/c I was the only one who signed up. I was so hoping I'd learn about this stuff in person.

Why don't you try an experiment? I assume you feel the hybrid is slow even when you aren't towing the kids? So, just swap the tires and put the 700x25s on the hybrid. 35s will probably run slower but it depends on tread and pressure. 35s just weigh more also and it's rotating weight.

You could be talking a lot of money to make wheel swap work since the entire drivetrain is probably waaaaay different. You may just want to invest in narrower faster rolling tires for the hybrid. I suspect the old roadie doesn have indexed shifting?

Why not just ride the roadie when you want to go fast and ride the hybrid when towing the kids.

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Originally Posted by SadieKate

Why don't you try an experiment? I assume you feel the hybrid is slow even when you aren't towing the kids? So, just swap the tires and put the 700x25s on the hybrid. 35s will probably run slower but it depends on tread and pressure. 35s just weigh more also and it's rotating weight.

You could be talking a lot of money to make wheel swap work since the entire drivetrain is probably waaaaay different. You may just want to invest in narrower faster rolling tires for the hybrid. I suspect the old roadie doesn have indexed shifting?

Why not just ride the roadie when you want to go fast and ride the hybrid when towing the kids.

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yes, I've thought of just swapping the tires, but I don't think I can put 25s on the hybrid rims. I don't know exactly what width rims these are (they're matrix 750s, haven't found specs anywhere). According to Sheldon Brown's site, I can probably put 28s on. But I don't know that I'd be happy with skinnier tires when I'm towing the kids, that's why I thought about using the second set of wheels. The hybrid (as it is) is perfect for the family outings and since it's alu it'll be great in bad weather (I'm also getting fenders).

When I ordered the hybrid, I hadn't ridden the road bike in about 15 years, and felt really unstable on it, b/c of the tires, the drop bars, and the downtube shifters. Plus, I had a horrible time on even the tiny hills near our house. But in the 5 weeks it took LBS to get the hybrid, I've become much more comfy with the tires, responsive steering, and even the body position, but still am not crazy about the downtube shifters and narrow gearing. Although, I am certainly improving on the hills! So I'm not totally satisfied with that ride either.

In a perfect world, I'd just buy a new road bike, but can't really justify that expense now. So I thought about upgrading the road bike, or then I wondered if just decreasing the rolling resistance on the hybrid would be satisfying enough. It seemed like getting a 2nd wheelset for the hybrid would be a cheaper option (especially if I could use my roadie's wheels or buy a used bike to scavenge the wheels) than upgrading the roadies crankset , FD, shifters, etc., not to mention brakes from the other thread!) and would be a fun project if I knew that reducing from 35 knobby tires to 25 smooths would give a serious increase in performance. With quick release, it just wouldn't be that big a deal to switch wheels in addition to hooking up the trail-a-bike for those family outtings. And, if that was a good ride, I wouldn't neccessarily ever put the wheels back on the roadie so I wouldn't have to worry about backwards compatibility. But keeping the roadie intact would be one advantage of trying to snag some cheap 700c rims from a garage sale ;)

Thanks for your input.

What kind of hybrid is it? Model and drivetrain components?

Rear Derailleur
Shimano Alivio

Crankset
Shimano TX71 48/38/28 w/chainring guard

Cassette
SRAM 850 11-32, 8 speed

Rear hub
shimano RM60

Dr, I started a thread on bikeforums where I've gotten great info in the past. I asked if anyone knew the narrowest tire you can run. Matrix rims appear to be made by Trek/Bontrager but I can't find much info very quickly. We'll see what responses we get.

Your best option is probably going to be narrower tires. As I thought about this whole thing I realized that you've got more than drivetrain incompatibility with your old road bike. The spacing of the rear hub on your Trek is 135mm. The old faithful roadie is probably 126 or less. This is a no go. You might luck into a set of cheap wheelsets on Nashbar or Performance but you must have 700c wheels with a 135 rear hub, an unusual combination for after market wheelsets. Usually only comes as OEM but you never know. Search eBay, ask your bike shop, post on bikeforums, etc. I'll go do a few searches also.

Thanks SadieKate, I'll check over at bikeforums.

There hasn't been much response over there. Someone else asked the same question and got a lot of different answers. I think your best and fastest route will be to call Trek's technical dept. Phone number is on their website.

I did see some 700 rims with 135 hubs on Nashbar but didn't look at the tire width specs. They were pretty cheap.

I have 25's- Continental Ultra 2000's - on my hybrid that would have come with 35's. I have a Trek 7500FX. No problems at all with the rims - LBS guy knows my riding (sometimes better than me) and encouraged me to go even smaller than the 28's I'd gone to on my heavier Giant Nutra.

(Ultra 2000's are more expensive than a lot of tires, but they last me 5000+ miles so it's a worthwhile investment.)

Thinner tires are much, much faster (tho' the specific tyre might have something to do with it too).

Oh, and also make sure you've got 'em inflated up to snuff. Almost invariably, when I'm wondering why I'm haveing to work so hard, I'm underinflated.