chain rollers
 

Yes or no?

My dr350 has bother an upper and lower chain roller. The upper one is so far away from the chain that you could well believe it would never make contact, yet when I bought my well used second-hand bike this part was thoroughly worn in every respect. The lower roller was siezed, the bracket on the frame it attached to bent, and the chain was just gourging a trough through the static plastic.

I replaced the lower roller (and straightened it's mount), but the cheap quality replacement vibrated loose and dissapeared. After this I did some thinking and decided the bike would work well enough (better?) without it. I did somewhere close to 20k miles on my trip to Mongolia last year without this lower chain roller, using just one chain and one set of sprockets.


But my question, is whether these chain rollers serve a purpose for a distance traveller? The lower roller on my dr350 would basically be in contact with the chain all the time at a normal tarmac cruise. Would this help prolong chain life by keep the chain taught and making it hug the front sprocket? Or would the friction and heat caused by the contact act to damaage the chain in someway?

I can't really answer your questions. But on my 650 the bottom roller has done over 190k, but I don't think it touches all the time. The top one broke off, taking a piece of the frame with it. I have left it, but the chain is very slowly chewing away the already skimpy chain guard.

Our German DR650 specialist sells this as a replacement for the 650:

Hessler RT Online-Shop - chain pulley rebuilding UPPER side HRT-KF-O

It's a solid piece instead of a roller. You can ask him about the 350, he lists a few parts for it.

Surely the top roller is just for very heavy off road use (landings!) and not ofter used?

I wouldn't bet on it. It depends on how your bike is set up. I remember when I first bought my DR650 it would bottom out on undulating sealed roads, no luggage and I only weigh 80kg fully kitted out. Just add luggage to any bike and ride on an uneven road and you will probably bottom out often or come close.

I think you've figured this one out. Like the DR650, the DR350 does not really need the lower roller, especially for mostly road travel. I've ditched both upper and lower on my DR650 because they made so much noise. No chain derailments in 30K miles and two chains/sprocket sets. Quite a bit of off road use with luggage and bottoming. No worries so far!

As long as your chains/sprockets are lasting well I think you are fine. To me, this is key.

I would look along the chain path: swing arm, rubber swing arm slider, frame rails, chain guide and the area around countershaft sprocket. Make sure the chain is not abrading metal any where or rubbing where it shouldn't.

Many neglect the swing arm rubber Slider and let it eat up the swingarm. Replace if worn out.

The other thing to check is the rear Chain Guide, the plastic thing just ahead of the rear sprocket. These wear out eventually. (I assume the DR350 has one?)

As has been said, the upper and lower rollers are mostly there for extreme off road use in big whoops where suspension is repeatedly bottomed. In these condition your chain would need to be pretty loose, and without the rollers it could skip a tooth or de-rail, but unlikely. Keep the chain adjusted correctly for road riding, you should be fine.

Just keep an eye out but I would say NO ... You do not need either one. Maybe check out a DR350 board to verify, get DR350 owners opinions?

:mchappy:

Roller wear depends on your how tight you run your chain, sprocket size, suspension settings etc etc ..

I'd keep them on though. Any flap or jumping is helped to be kept in order with the rollers.

Roller.
 

Hi.
Had a bit of roller tinkering on my o'l DR350.
Just be aware that some folks swap the upper roller with the lower one when it wears giving the impression that the upper roller takes a lot of chain pressure.
I ran it for quite a while on off road without a roller and although it did "de sprocket" once even though there was a nylon chain guide on the swing arm. I replaced the roller and never had another issue.
Just so long as your suspension sag and chain tension is set up ok it should be fine for the most part.
I replaced a nylon chain "rubber" on an XR650L with a roller and it was fine, there are a few rollers with sealed bearings (All balls) which should stop siezures after water and mud abuse!
Have fun.
Dave.