Zeps Posted August 12, 2010 Share is there a real difference between road and MTB RD pulley wheels? Is there a difference between the top and bottom ones? Shimano in this case, will it make a difference to the shifting that is significant? Link to comment Share on other sites More sharing options...
stewie911 Posted August 12, 2010 Share Usually the top pulley is just a bushing with a bit of sideways play for better chainline or whatever. The bottom one may have a bearing of some kind. On my campag record derailleur both is the same though. As long as the pulleys is the same size then you should be able to change between road and mtb. Link to comment Share on other sites More sharing options...
LEMOND Posted August 12, 2010 Share As far as I know there is no difference between Rd and Mtb but there is a small diff between top and bottom pulley. top pulley has ab 1mm of play so as to be able align itself with the gear. Then again I have installed them the wrong way round by mistake and could not detect any shifting difference. Link to comment Share on other sites More sharing options...
Johan Bornman Posted August 12, 2010 Share There you have it. Just to point out, the floating pulley doesn't float to improve changes but rather to accommodate slight adjustment errors and thus still run quietly. If you install the wrong ones top and bottom, shifting will be as good or bad as before but the drivetrain could be more noisy. Some brands have offset pulleys where the centreline of the pulley is not in the middle of its axle. These cause huge problems when installed improperly. Link to comment Share on other sites More sharing options...
David Marshall Posted August 12, 2010 Share No real difference between road and MTB pulley wheels in my opinion. Some MTB pulleys have bearings instead of bushes, supposedly to operate better in dirt and mud but I prefer bushed pulleys myself - you can ride a lot further on a worn bush than a shot bearing. The top and bottom pulley wheels look the same but the top one is slightly narrower than the bottom. This allows some lateral movement on the pulley bolt as the chain moves. There should be no play on the bottom one as it should be held directly under the relevant sprocket when you shift with the RD. I assume that getting this wrong could significantly affect shifting performance but I'll bet there are a lot of bikes in use where this is the case. Link to comment Share on other sites More sharing options...
David Marshall Posted August 12, 2010 Share You guys are busy tonight. I open a post with no replys and by the time I've had my say I'm 4th in line! Link to comment Share on other sites More sharing options...
stewie911 Posted August 12, 2010 Share Was thinking what the hell is going on. I suppose you've got answer now. Four guys with the same posts Link to comment Share on other sites More sharing options...
Zeps Posted August 12, 2010 Share Thanks guys! While changing the chain/cluster on my workhorse MTB I noticed that one of the hanger screws had been lost and that the pulley wheels were in a terrible state. So found a screw and some pulley wheels in my 'goodie' box but was unsure where they came from. They were in good nick and appeared very similar. Have anyway now put them on and I am sure that my training ride tomorrow will have way better shifting and SPEED Link to comment Share on other sites More sharing options...
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