I have only tried 14 in front and a didnt like it at all..

Yes was thinking of changing tyres, may get some siracs or one of the cats paw style tyres like Heidenau as I like those.

tires? I'm looking at the new Continental TrailAttack 2! I've done 7k HARD kms on my TrailAttacks and they still hold like glue to the road!

Just ordered a 43 rear from wemoto apparently its listed for a 660 xtz. Lets hope it fits as I've got a 280 mile road ride next week Ha

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Why you going down? 45/15=3 43/15=2,86 iam thinking that you lose torque and maybe get a little more high speed? Jens have 47/16 = 2,94 and i would think you can feel any difference to 45/15? When i changed to 45/14=3,21 i got more torque but i didnt like the gearing in the beginning, 1 and 2 gear was to short.

Rear Sprocket
 

My 86 had a 15 42 stock. That is a good ratio for street only, but a little too tall for trail work in the mountains. Early on I went with a 14 42 which is a 1 to 3 ratio and works great!. I just replaced both sprockets and chain with a new xring chain with 15 stock and 45 sunstar which is of course 1 to 3. I like that ratio as I either am running around town or in the mountains. I like the larger sizes as the chain has to "bend" around a larger radius and should last longer.

I can only go on the changes I used to make on my xr400, which was similar to where I am now. Yesterday I went to Worcester from Cardiff so I chose to go M4m5 and 65/70mph was up to 4500 rpm and it was ok. 70 is a nice speed for this for my own personal views. If by dropping a couple of teeth on the rear just drops it closer to 4k rpm or a tad above I will feel the bike will thrum along just fine. I have got to buy new chain and sprocket anyway as they are fubar so I may as well try something different

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xtz660 front and rear sprockets is the same as xt600e, so yeah, they fit.

The earlier xt600 models from the 80's-ish had different internal gearing, so remember that when we try to compare. Also, different size reartires can easely alter the "gearing".

You dont cant gain torque by changing the gearing, you cant force the bike to gain more power like that. But you will have more torque avalible at the same rpm, with a "shorter" gearing, compared to a "longer" (14/45 compared to fx 16/45)

Yes i didnt write that correct, bike dont get more torque but you change the way of using the bikes torque. But why use 16/47 when its so close to the original?

Because I think thats best for me, so thats what I order when I buy new chainkits. Also, the bigger sprockets should give sligthly less wear.

I have 2 sets of front and rear wheels, and sprocets: 13, 14, 15, 16, 42, 45, 46 and 47. I use the bike for a lot of different stuff, and have played around a lot with sprockes to find what suits me best, for various situations.

I've made a new cover for the CS sprocket, and have a list on my phone where the snailadjuster have to me with the different sprockets, to give a correct chainslack. That meas I can change the CS sprocket in just about 5minutes.

Going from 16/47 to 14/47 really changes the bike. That combined with 2 sets of wheels, one for tarmac, and one for offroad, you can make it a completely different bike in around 20-30minutes.

Oeh, sorry, got carried away. Hope it explains it :oops2:

Well Ive had new chain and sprockets fitted. I already had a sunstar 15t in my garage that I never put on my old 660Tenere and I bought a 43t JT sprocket from wemoto. I couldn't undo the front sprocket nut so I took it down my local shop and had him do it for 20 quid and I bought a JT X ring chain from him anyway for £44.
What I never knew.... because I never looked was I was running a 14t front and a 45t rear. I rekoned I must have been standard gearing as the performance of the bike seemed to be as Id had read about i.e about a 65 mph cruising speed at about 4k rpm.
however now on a 15t/43 combo its been transformed on the road, nice spread between gears and now at 70 mph its at 4k rpm. even with a tom tom gps on at 70 the gps is showing 68mph.
Putting that into perspective for me. My 09 Tenere 660 that I sold as I was skint!! Felt pretty quick and cruised on the motorways at 75/80 mph but the electronic speedos on these are known to be 10% over !!!
So the old 600 XT is producing the goods for me so far

20quid to undo the front sprocket nut? that's crazy! :o
you can almost buy an air impact wrench and do it yourself for that price!

anyway, at least you got it sorted!
Safe driving! ;)

Ha no I tried to undo that first and then got him to do the lot for 20 quid.

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One thing I did forget to add, which may be good for others for future reference is the sprocket is a JT-857-43. Listed for a MZ Mastiff, Xt600ZE,XV250 and XTZ660 89-96