Model 49 sprockets

[hugo_furst]

Hello,

What is the standard original sprocket gearing for the 1970 Model 49 (Sherpa T?)  And, are 520 sprockets/chain recommended?  Thanks!

[bullylover]

I`m not real sure what gearing the M49s had but all the later ones 11/46 works pretty well and this is for a 520 chain.

[sherpa325]

14/52 for the 250 bikes using the 1/2" chain. The first 325's M92 used 13/52  1/2" chain.  The later bikes up to the 198/199 used the 11/46 5/8" chain which works out to be very close to the 13/52.

[hugo_furst]

Thanks, Bully and Sherpa.  My bike has 428 chain (Renold! but worn out.)  I counted 52 on the steel rear sprocket, have not counted the front yet, and of course, I don't know if the gearing was changed before I got the bike.

[woody]

Gearing is personal really, or needs to suit what your riding entails, trials or just trail, playing about.  For trials I find the standard 11:46 of the 520 chain a bit high as sections are a bit tighter than they were when these bikes were designed, I've used 11:48 on my M49 and others which means less clutch use in tighter sections.  As mentioned above, 14/52 was the standard M49 gearing on 428 chain and other early bikes, but that is a bit higher than the 11/46 combination on a 520.  Whether you use 428 or 520 won't make any difference to the bike but you might find there are more options with 520 rear sprocket sizes although there is only an 11 tooth option for the front

Edited February 20, 2023 by woody

[hugo_furst]

Thanks, Woody.  I rode the bike a few times with the ? / 52 gearing.  It certainly felt slow in first to me, so much slower than my modern bike (Montesa-Honda 4RT 250,) I was laughing as I rode.  Slow motion!  When I count the front sprocket teeth I will report back.

[hugo_furst]

So, the bike had 13 / 52 gearing, which worked fine, and was so much easier to ride than my 4RT.  To clarify, I was laughing because I was having fun, not because I regard myself as an expert with cat-like reflexes.  I don't! I'm not!

The bike is also fun on the open trail.  It has a seat.  It has mudguards which actually stop mud. Good power, and good gearbox ratios, nicely spaced for good acceleration, (unlike the modern 5 speeds with three low gears then a jump to fourth and a jump to fifth, not fun for trail riding.)  If I'm not mistaken, Sammy Miller won the Scott Trial three years in a row on his Model 49, then Malcolm Rathmell won, but I'm not sure if that was a Model 49.  So, the Model 49 ain't slow!