Converstion kit and donor bike gearing.

[RandoTy]

If I use a YFrame mountain bike for a conversion, can I get the gearing changed, in general, to be more road appropriate? Meaning, I'd like to get more flat speed than a normal mountain bike, but still would like to be able to climb. I am contemplating this bike to be a randonneuring bike. Meaning, going 200K, 300K, or longer distances.

I ask, as I did my first 200K Brevet on my Specialized 1999 Mountain bike , which I had changed to road tires, added fenders, etc.. I did ok, but really lacked on the flats. I remember when I looked into modifying the gearing on that bike, it turned out to be more trouble than it was worth.

I know it depends on the bike, but I guess I am wondering if it is possible, in general, and if so, what bikes would be good donor candidates?

Thanks,

Ty

 

[Charles.Plager]

Yes, it's very easy to change

Yes, it's very easy to change the crankset used (just take the old one off the old bike and put a different one on the conversion kit).
I've got a 50/39/24 on my conversion and a 48/38/22 on my Sofrider.

And if you want a different cassette, it's easy to go to a cassette (with the same number of speeds) with smaller cogs with no problems at all. If you want a bigger number of gears, you may need to change the rear derailleur to a longer cage.

 

[Doug Burton]

Charles, as usual, is correct...

Something else to consider is how the crank sits on the bottom bracket axle. Road cranksets tend to sit farther down on the bottom bracket axle taper than MTB cranksets. So if you change the cranks and keep the old bottom bracket, the inner chainring may end up too close to the center of the front tube (this is called the chainline dimension) and you'll have trouble shifting into your lowest chainring.

"Trekking" cranks (generally those having a 48 tooth large chainring) can go either way with fit on the bottom bracket axle taper.

Usually a good idea to get a crank with its suggested bottom bracket.

Cheers,

Doug

 

[Charles.Plager]

Doug made a very good point.

Doug made a very good point. I considercranksets and bottom brackets a pair. You want to make sure they match (and I should have been more explicit).

 

[RandoTy]

Thank you both, and a follow-up:


So probably donor bike from Walmart, change out the bottom bracket and cranks to a new matched set, should work out ok, correct?

I don't see a downside to that, and I can always get better brakes, etc. down the road, as I'm sure the Wallmart components are crap.

It would be less expensive, though not as nice, as getting the V2K and buying everything. Functionally, it should be ok., do I have that right?

Thanks again for answering these newbie questions. I am scouring the forum for answers, but it's a big forum!

@Charles - I read your blog posts. I was glad to see your new option gave you some decent climbing ability. That is my main concern here. In the SF Bay area, most of my rides have a lot of climbing. I want to be able to do it as least half-way decently.

Thanks again,

Ty

 

[Charles.Plager]

Hi Ty,
I think you've got

Hi Ty,

I think you've got it.

Definitely get rid of the knobby tires. You may want to swap out the rear wheel/cassette with a upgraded derailleur sooner than later (particularly if you are like me and don't like large spacing between gears), but that's not crucial.

You can find the parts I used for my Cruzigami Mantis here. The triple crank and bottom bracket work well and you can swap out the granny for a 24T (as I did) to really help with the lower range.

Good luck. Let us know how it goes!

Charles

 

[RandoTy]

Opinions on another doner bike possbility sought

Hi everyone!

A friend just offered me a Mongoose Domain Aluminum Y-Frame Bike for free. Funny, but I have always given them a hard time about this bike, as it is a Wallmart cheepie, but it works fine, and it is free.

With the idea of replacing what is needed of course, do you think this will do for a start? At least get my feet wet, and then upgrade gearing, etc., as time goes on, and then eventually moving up to a Sylvio or Vendetta?

I used a similar strategy when I started randonneuring in the first place a couple of years ago. I used my commuter bike for the first two rides, the last one a 200K on my mountain bike, and then got a Salsa Casseroll, which is basically an entry level randonneuring bike, and I gradually upgraded components.

Originally, I was going to stay with DF and move up to a nicer, lighter weight steel bike, but a friend of mine with the
SF Randonneurs, curse him... , planted this bug in my ear about bents. It just seems to make sense to me to be comfortable over 200, 300 miles.

And not have my "what-what" numb go numb after 75-100 miles anymore either...

Ty

 

[Charles.Plager]

Hi Try,
Even if the bike is a

Hi Try,

Even if the bike is a complete failure (which I'd highly doubt), what are you out by trying the bike? Nothing.

The biggest thing too worry about is seat height and it looks pretty good there.

Go for it!

 

[RandoTy]

Thanks Charles! My thoughts exactly!

It's definitely adult sized, so I think l'll be ok, and it "works," so what the heck?

I really like the whole conversion kit concept. Really, no drawbacks!

After all, once I get my first iteration going, I can always upgrade to better components and/or donor. If I really want to go all out, I can then simply go Sylvio or Vendetta and sell the conversion kit. From what I can see, they definitely have good resale value.

You can't go wrong either way!

Ty