I tried to order a rear SuperSpox sprocket from Off The Road and they are out of stock of the standard 45 tooth version but the did say this:

"If you buy new sprockets, you should think to take 15/48 instead of 15/45 (stock). The bike runs much, much better with the shorter gear ratio."


Would this be true? What difference to performance, pull away etc do the extra teeth make? Any advice Kev?

ps reason for SuperSpox is that the Renthal alloy has worn quickly.

From my push bike days messing around with gears and wheels etc the 15/48 tooth combo should give you alot more get up and go, 0-60mph times will drop but all the thing will probably want to do is wheely. Also every gear will feel shorter so there for insteed of being able to do say 20mph in first you will only be able to 15mph or so.

The only big draw back to this mod is that your top speed, or comfy cruising speed will drop, by how much dont know.

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interesting as I also thought the same as you describe, but the guy at OTR replies this...

"you will not "feel" on teeth extra, but if you take it about 3 teeth more, you will have a much better acceleration. The bike feel much more powerfull in every rpm.

Very important: You will NOT have a reduced high speed! This indicates that this is the correct gear ratio for the bike - the stock ratio is only because of the emission rules and makes no sense in a technical way!"

Confused now, may try the 46 and see what happens.

Don't forget that your speedo will read incorrectly if you change to a different tooth sprocket.

Have you thought about D.I.D. chains. I was going to get a Renthal chain and sprocket myself but was informed that they are not much cop compaired to a D.I.D. chain and sprocket set.

That doesn't add up. If I can do 109 mph and hit the rev limiter then if I change the amount of teeth on the sprocket then I will accellerate faster but I won't hit 109 mph. As far as the emission rules, I think he's talking out his backside. lol.

Stick with standard and you won't be over stressing you gear box.

I also have a suspicion that he is talking bo**ocks and is just trying to sell what he has in stock. I will keep up the conversation with him though and ask about the speedo and what emmissions.

He did mention that 90% of his sales to XT660X owners are the 48 tooth variety, I could probably understand this for the R if being used off road.

I have run my bike with 15/47 for sometime now. The bike is much quicker from low down with better pick up through the gears, top end is still around the 100MPH. The bike is easier to ride at slow traffic speeds.

My speedo has been corrected with a Speedo Healer.
http://www.xt660.com/showthread.php?t=3266

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Mods that I have done to my XTX's

My 04 XTX
Stage 1 & 2 DNA filters / Kev fuel mod / snorkel mod / Drilled air box mod / Engine breather mod / Fork Spacer mod / 15w fork oil /
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My 07 XTX
Raptor 700 cylinder 102mm / Modified Crank Case to take a 105mm Raptor Cylinder / 11:1 102mm JE Raptor piston / Stage 1 Raptor Hot Cam / Ported head / Colder Spark Plug / +2mm Throttle body / DNA stage 1 & 2 filters / Modified Air Box / Snorkel removed / Worry Brothers stage 2 filter cover / 6mm & 8mm Bolts Replaced with Titanium Bolts / Recovered seat in Black / O2 Eliminator /

My 09 XTX
59HP at the rear wheel / Stage 2 Raptor Hot Cam / DNA stage 3 Air Box / Carbon Can Exhausts / Modified Exhaust Link Pipes / PCIII With Custom Fuel Map / Wideband Commander O2 Data logger / LCD100 Dyno Jet display & fuel adjuster / 2500 OHM HT lead instead of a 10K OHM XT lead / Extra Coolant Cooler / Protaper Fat Bars / Tail Tidy With LED Tail Light / OKE Protection Knobs / LED indicators / AIS blocked / Modified rear sprocket rubbers / Rear Foot Pegs removed / 09 ECU With 02 Sensor Changed To A 06 ECU / Complete wiring harnes Changed from 09 to 04 / Home made LED resistor flasher / Hole drilled in the fuel tank filler neck to allow quicker filling / Modified Bar End Weights / Progressive front fork springs, 15W fork oil, forks lowered 25mm, used XTR rear links lowering the rear 20mm, rear spring one click stiffer / Changed front & rear guards from blue to black / 47T rear sprocket / Speedo Healer V4.0 / Kev throttle cam mod / Throttle grip mod / The new 2010 O2 sensor mod is out, works a treat, The new 2012 O2 Controller is out, PM me for details

Now ride a 2018 MT09SP ABS + TCS

My KTM 990 SMR Mod book. http://www.ktmsmt.com/viewtopic.php?f=13&t=4946

Hi Kev,

Feel better now that you can confirm no top end drop off. If I don't do the speed healer to start with is there a noticable difference in speedo calibration?

I don't see a conformation in Kev's post.

If you change your sprocket then your bike will accellerate faster but you WILL loose some top speed. FACT!!!

Agreed, but still getting around 100 is plenty. More concerned about the speedo calibration now, Speed Healer sounds great but this adds �60 onto the costs http://www.bikersdiscountstore.co.uk...do_Healer.html

Time to consider all I think. Maybe back to steel 45 sprocket