CigTech

Hey guys,

I made this bent and have a few questions.

With the MTB tires I can get it up too 16mph. my qustion is well road tires make it that much faster? Like 20 mph or so.

I have a 48t on the front gear and a 13t on the rear with 170mm cranks. If I put a 52T over higher on the front with a 160mm crank will it be to much for it? I do need a smaller crank due to the foot cleancer with the front wheel. Or would you guys leave the 48T and put a 160mm crank on it?

That's about it for now.

meb

The mountain bike tires are likely to be 4 mph slower or more.

I'd change the cranks for a plurality of reasons. The leading being the heal clearance. Reducing crank arm length will increase your gain ratio giving you a similar effect to a change of ratio.

You could always change the cranks first and then got to 52/53 or whatever later after you have tried changes to the tires and cranks. Your fder is probably a mountain bike and therefore has a curvature matching a 46/48T ring so will shift smoother on the 48 than the 52. A change in the rear sprockets could also help ratios.

As an alternative to road tires, you could go with mountain bike street slicks which will help reduce the rolling resistance on pavement and would fit the current tires.

World Tour

NICE!

I use slicks on my lwb, front and rear.

BlazingPedals

First, I'll say it looks like a good overall design. Steering geometry looks good, you've thought about providing a good chainline, (still needs a front derailleur post, though...) The first step to making it faster will definitely be to put some faster tires on it. Even cheap slicks will roll significantly faster. I like to use Huchinson Top Slicks - they're always on sale for cheap at Nashbar, and while they won't win any races, they perform OK and they wear well - which is more important for an everyday bike.

After you ride with the new tires for a while you'll have a better idea on whether or not you want to change gearing. I think you'll find you have heel strike no matter what size crank arms you use; so worry more about whether your feet like spinning in a particular size of circle. When you're ready to upgrade your crankset, your LBS can find you an inexpensive Dotek set in about any size you can think of.

kapnk

I'm not so sure those derailer idler wheels are built to withstand the forces of the drive side of the chain. You might want to prepare to replace them when they wear out, unless they are more than meets the eye. As you've probably read, lots of people use rollerblade/skate wheels or maybe fabricate some gear with a bearing. My idea was to take the hub of an old wheel and use that to reroute the chain.

The derailer pulleys are okay for the lower non-drive side of the chain, imo.

Otherwise, it looks great! How are you liking the seat? I was thinking of doing something very similar.

Kevin

Bikewer

My first attempt, using the general ideas of the "no-weld" bike, used the DR cage for a front chain guide. I rapidly tossed it and built my own out of skate wheels, and found I had to get the extra-hard ones at that.

I have refined the chainline on my version 2.0 and now am able to run almost a straight shot on the drive side from rear cogs to front crank.

CigTech

I replaced the derailer idlers with a cut steel piece and put a small bearing into the new idlers. It is a lot better then the stock derailer wheels and it cut down on the roll fraction and noise.

keith-pam

What is the frame made of. It has sort of a I beam shape which could really add strength. How are the pieces connected. It has a look of stiffness to the frame. Are those revits, I can't really tell from my little computer screen.

Keith

CigTech

The Frame is made of 2x4 lumber and 1/2" plywood. I have fiberglassed the frame to give it a sold frame.

FarHorizon

+1 on other posters' advice that road tires will add speed.

Only your knees can answer this question, IMHO. If you need the smaller crank for clearance, do it. Try the new, shorter crank out with your existing gears - You may spin so much that the existing gears will be fine & you'll have saved the price of the gearing changes. If you end up needing more ratio, then do it.

meb

Are you saying the fiberglass adds rigidity or was this merely cosmetic?