700c Road Bike / Commuter Project

[happycheapskate]

I'm interested in steel touring 700c and 27" bikes with Grubee or staton/BMP type gas motor kits.
Please direct me to proper threads.

 

[Tanaka40]

The 700c and 27" bikes were built for speed, not longevity. They can't take the constant pounding without failures. Lance armstrong and other road racers have a ton of back up bikes because they break so often. A mountain bike IS built for the pounding of the trail and road. The wheel sets and dual supension make it easier on the backside on ling rides like cross country. My question to you is why would you want to build a bike with no suspension???

 

[happycheapskate]

I expect featherweight aluminum race bikes might have "failures" even on 3000$USD wheelsets, with enough heavy use, and beating them up like the Paris Roubaix.

A generic Japanese steel 80's or early 90's road bike ought to be a lot tougher.

The bike I've got now has a suspension seatpost and thats good enough for 30.

I grew up racing road bicycles (cannondale etc), so I am familiar with them, and sure wouldn't use any 3.5lb aluminum frame for a motor bicycle, nor would I use any of the road racing wheels or rims I used to use.

I am talking more about generic and industrial stuff.

 

[happycheapskate]

re: no suspension. Because I don't trust the suspension forks I can afford, and can't afford the suspension forks I trust. Screw spending $300 on a mountain bike fork, or some kind of bloody hybrid 700c/29". This is rediculous. This is why the 50$ springers are so popular.

 

[Tanaka40]

check craigslist for bargains. Sometimes the best deas are right in your own area.

 

[happycheapskate]

I used to have a 700c road bike (Centurion, Japanese steel 80's touring bicycle with steel TANGE fork.) It rode nicely and had fat 36h Weinmann wheels that took a lot of the roughness from the roads. The fat 700c tire sizes (well not hybrid fat, but road fat, 28c or 32c even) fit the frame. If you use it the same way you'd use a road bicycle (on the road) something like that would be ok (steel stem and handlebars were strong), and fast!

Here is an example of a much lesser bike with 26 fractional size tires and a HT motor kit. Still turned out very nice. Probably a joy to use.

 

[Tanaka40]

WOW , that looks nice . I have a royce-union 80"s vintage bike in my garage gathering dust. come and get and you can convert it. (tire size 26x1-3/8)

 

[happycheapskate]

Thanks for the offer but you are far away and the shipping costs would be terrible.
Perhaps if it is a size that fits you, it might call you to slap a grubee kit on it yourself.

 

[george_n_texas]

Right on all counts

Its do-able, but has some major inherant problems.

You will find that you might get frame and wheel mount failures because of the 0-100% torque on electric motors (hence why they are used in train motives and such) - also the skinny tires will be taking a fearful pounding and the last thing you want is a wheel collapsing on you at speed.

The thing with a 700c bike is that its optimised for speed given that the motive power unit is going to be a human... its the superbike option when all you have are your legs providing the go. Therefore they are generally pared down weightwise in order that they can make the most of the power available.

The problem comes when you try and motorise them because there simply isnt any free tolerance to stress and vibration (the latter not being so much of a problem in this case) that something like a Cruiser frame or MTB is designed for.

Most of the kits will work with the larger wheel (hub motors are just a replacement of the hub that is laced in), although that will change the gearing and they should manage to make the cruise speed you are aiming at without problem... my only worry is the durability of the frame/wheelset with all the extra weight and speed induced stresses. You might loose a little acceleration with the larger tyre (higher gearing) but it is entirely possible to do.

This is only my personal opinion you understand, but I think you would end up with a more reliable and less highly strung machine if you were to get one of the hub motor kits and put it on a reasonably priced MTB frame... since if you are anything like me - you are likely to use the machine more as a electric moped... and in that case weight saving is not so much the issue..

hope that helped...

Jemma xx

I'm gonna try mounting my e-kit on my cheap wal mart paver...my theory is if you peddle till you get a little speed likely 3-5 strokes hard the hub motor will not jerk if you slowly excerate then braking is the big issue.

 

[Tanaka40]

I'm gonna try mounting my e-kit on my cheap wal mart paver...my theory is if you peddle till you get a little speed likely 3-5 strokes hard the hub motor will not jerk if you slowly excerate then braking is the big issue.

That is true George, however the torque can still slowly open the dropouts and allow the motor to spin. be careful amd check the bolts frequently. :helmet: