View Full Version : Idler pulley placement
John Lewis
10-10-2008, 01:40 AM
On the Wolf the Idler is pretty close to the sprocket. This makes for some rather extreme angles on the chain to the big or small cog.
Is there any reason, other than a slight decrease in ground clearance, that the idler could not be located further forward on the reinforcing piece under the seat.
This gives a longer chain line and much less angling of the chain to the side. I can't see a problem and I think it might be an improvement. Am I missing something?
John Lewis
John Lewis
10-10-2008, 05:43 AM
I have taken some pics to show what I mean.
You can see in the normal idler position the extreme chain angles and the improvement when the idler is moved to give a longer chain section.
The idler is probably not that much lower. Maybe 1 1/2" and I can't see a problem. Also the chain is not at as an extreme wrap on the pulley hence lower forces and marginally less drag perhaps.
http://i254.photobucket.com/albums/hh98/lew2au/Chainlines.jpg
John Lewis
ggriffin924
10-10-2008, 09:34 AM
I have a bit smaller idler its only about 3 inches in diameter so the angles are not as bad, but your right the chain doesn't have much room between the freewheel and the idler. I tested out having the idler slide from left to right on the bolt, and I liked how it shifted and also seemed like a better solution, really cut down on the angles. But since my idler only has one bearing, with the nut loose I got to much idler wobble for my own comfort. I tightened it back down and I am pretty happy with the shifting for now, I'm using friction shifters, I plan on an upgrade to indexed shifters after the next payday or two.
-Griffin- :)
SirJoey
10-10-2008, 11:47 AM
Here's another possibilty, John. Use Richie Rich's floating pulley method, like I did. A simple solution which works great!
http://img390.imageshack.us/img390/3422/floatingpulleyyi9.jpg
Additionally, based on your pics, you need to get your pulley in closer to the frame,
while still allowing it to float outwards.
http://img185.imageshack.us/img185/9206/signaturehalloweenvr0.jpg
Sparky
10-10-2008, 01:35 PM
mine floats. works good.
John Lewis
10-10-2008, 10:27 PM
Thanks for the info guys. My idler has a single bearing and is quite wobbly. I don't know how it will go sliding on a bolt. I'll do a mockup and see how it goes.
Joey, In your picture and in the plans I see no provision for a chain keeper around the pulley. What is the likelihood of the chain coming of the pulley? If you were to back pedal and the chain come loose it seems it might miss the pulley on tightening. I've used keepers on my other bikes and will probably do so on this one too.
John Lewis
SirJoey
10-10-2008, 10:53 PM
John, so far, I've never had a problem with the chain coming off.
There's never any slack in it, even when back pedaling, so it's not a problem.
http://img185.imageshack.us/img185/9206/signaturehalloweenvr0.jpg
AtomicZombie
10-11-2008, 01:47 PM
I have never had a chain pop off the idler of any bike or trike either. I had the Marauder, DWolf and LodeRunner out at camp several times, and seen some nasty washboard roads.
Brad
jimFPU
10-11-2008, 05:15 PM
Of course Brad, that doesn't count the shortest ride...I think that was the Fighter video I saw...LOL!
AtomicZombie
10-11-2008, 07:44 PM
Yes, that was indeed one short ride. Funny thing is that, the chain was still in the idler groove even after the bolt weld failed!
Brad
Maddog
10-11-2008, 08:08 PM
A weld failed? Was that the one you you were showing Kat how to do?
ggriffin924
10-14-2008, 01:04 PM
For the sliding pulley is it the bolt moving with the pulley tightened between the bolt end and a nut? Or does the bolt the pulley is attached to just slide back and forth through the frame? Just wondering, mine is working but I think it would be better with the idler moving some from left to right.
-Griffin-
AtomicZombie
10-14-2008, 02:40 PM
I had only a small tack weld on the idler pulley bolt. Forgot to finish that weld before the test run.
Brad
A weld failed? Was that the one you you were showing Kat how to do?
SirJoey
10-14-2008, 10:15 PM
For the sliding pulley is it the bolt moving with the pulley tightened between the bolt end and a nut? Or does the bolt the pulley is attached to just slide back and forth through the frame? Just wondering, mine is working but I think it would be better with the idler moving some from left to right.
-Griffin-
Actually GG, the bolt is stationary. Notice in my pic, it's double-nutted on the left side of the frame.
The inner nut is welded to the frame. Then, the bolt is screwed through it, & a second nut is tightened down on the protruding threads,
making the bolt adjustable, as well as removeable/replaceable. Then, the pulley slides back & forth on the bolt.
http://img185.imageshack.us/img185/9206/signaturehalloweenvr0.jpg
John Lewis
10-14-2008, 11:44 PM
Well after much thought I have put the pulley forward on the short reinforcing piece under the main tube. Gives me a better chain line at the expense of a small loss in ground clearance. Sliding pulley was not an option unfortunately with this pulley otherwise that's what I'd have done.
I drilled and threaded a piece of rod internally and welded it through the frame for the bolt to screw in. If I get a better pulley I can alter it to sliding. I may weld in another threaded rod in the normal position then I can try both.
John lewis
John Lewis
10-23-2008, 11:27 PM
So I finally made the choice and put the idler down on the reinforcing piece. It gives a better chain line and works great. Here is what it looks like. The photo makes it look close to the ground but there is plenty of clearance.
http://i254.photobucket.com/albums/hh98/lew2au/Pulley-Loc.jpg
I don't know why but I also had to lengthen the deraileur support arm. I used a bit of a spare deraileur for that. May have been needed because of the new pulley location perhaps.
http://i254.photobucket.com/albums/hh98/lew2au/Derailer2.jpg
John Lewis
jimFPU
10-24-2008, 10:06 PM
That looks great mate! I may have to relocate mine in a similar fashion for chain line improvement.
AtomicZombie
10-24-2008, 11:40 PM
Looks good. How is the gorund clearance like that?
Brad
John Lewis
10-25-2008, 01:27 AM
Looks good. How is the gorund clearance like that?
Brad
Hi Brad,
The pulley is 4" . The ground clearance is 6" to the Pulley or 5" to the bottom of the chain management cage. I can get this to close to 6" when I shorten the chain. At present I'm taking up slack by rotating the cage back. This results in less clearance.
The clearance on or LoGo Trikes is only 3" and has never been a problem. You could always add a little skid pan if you were worried about strikes.
John Lewis