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41 Tooth Rear sprocket on T-120?

23K views 57 replies 23 participants last post by  aj7840 
#1 ·
The 37 tooth rear sprocket makes for just a crazy high geared bike? I can run 95mph down the freeway turning 4.000rpms. Seems really over kill. I'm still in 5th gear doing 80. I saw the thread about the 39T that one of the forum member made but I am not that skilled. :) I do know the Thruxton carries the 41T rear. Has anyone put one on their T120 yet? Wondering if it'll solve some of the 1st world problem woes with the T120.
 
#3 ·
I was the one who made my own and 39T really is the ideal one.

I'd like for the people that are interested in a 39T rear sprocket to call the sprocket companies asking for one. That way they hear the demand and will start to produce them.

The two most likely to produce one is JT sprockets (770-948-8880) and PBI (503-645-6500), both are easy to contact with real people answering.

When I asked about them they both indicated they'd produce one if they saw the market for it.

The OEM sprocket is made by Sunstar but they are a huge company and are not as likely to respond to request, but maybe....

I'm really hoping by the time mine wears out there is one for sale.
 
#5 ·
I was the one who made my own and 39T really is the ideal one.

I'd like for the people that are interested in a 39T rear sprocket to call the sprocket companies asking for one. That way they hear the demand and will start to produce them.

I'm really hoping by the time mine wears out there is one for sale.
Might be worth contacting Renthal...they have the 2016 Bonnie on their website, but the smallest sprocket is 44T ??? and it looks like it lists them as a 520, and not a 525...maybe a screw-up on their website?

http://road.renthal.com/shop/fit-my-road-bike/
 
#8 ·
I did contact Supersprox, they told me 41T was the smallest they could go for the Triumph.

Did you get them to do a 39T for the watercooled bikes? Do you have a part number for it?

I would have bought one of their's if I could. I have one of their sprockets on my Ducati Sport Classic.
 
#12 ·
crossing my fingers. . .

I contacted Supesprox and they were really helpful and I purchased a 39T Stealth and it is listed as T120 Bonneville. Bummer if they are that flailing and send me one for a T100. . . . They didn't change me yet so I'll cross my fingers. . .
 
#18 ·
Hoping TheMattman finds his part number and/or receipt (no pressure. . heh heh) . SuperSprox doesn't seem to be able to get to the bottom of it? That is frustrating in its own. Definitely wanting to try the 39T rear. I also found a place called MotoTrio but you need to speak Vietnamese to understand the website. They are doing some cool stuff with the water cooled Triumphs.
 
#19 ·
Think we have a winner. . . . .

Just got off the phone with Supersproxusa. Look like the Daytona 675 used a six bolt sprocket. Same as the T120. They can custom mill them in one day and offer free shipping but. . . . . . . they are $114.95. ouch! Here is the link below if anyone wants to risk. I am ordering mine today. . . and will let y'all know.

https://www.supersproxusa.com/products.php?cat=1115500

You have to scroll down to the CMC on demand section and choose 39T and the color you want.
 
#20 ·
Its the Daytona 2006-2017 6 bolt that you order not the 2003-2004 Thanks to everyone working on this solution. Really a pity Triumph has been of no help The service department at my local dealer wouldn't even give me the stock sprocket measurements Told me 39T would interfere with the ABS/TC. Any thoughts on 40T vs 39T as this sprocket is available in either
 
#23 ·
This has been hugely interesting. I loaded the '16 T120 specs onto Gearing Commander and it confirms that the stock 17 tooth front sprocket works best with a 39 tooth rear. A 41 tooth rear would also work well, and both are possible with the standard 100 link chain. So there is a choice which will depend on your riding circumstances. From a chain and sprocket longevity point of view, I would avoid going down on the countershaft sprocket as well as avoiding 38, 40 and 42 tooth rears. I think Supersprox still have their listing wrong in offering #RST2012 as this is the number for the 865 Bonnevilles. They should be listing #RST2014 for the watercooled twins. PBI Sprockets have available their #9087, which comes in a huge range of sizes (including 39 and 41 tooth) for both 520 and 525 chains priced at around US$55.00. These are made of aluminium and come only in silver, but at half the price of the Supersprox I can live with that.
 
#29 · (Edited)
During my search for suitable rear sprockets for the T120, I just couldn't find something suitable in steel. I've never been a fan of aluminium sprockets, but checked what others have experienced anyhow. What I found is that there are a lot of people saying they wouldn't use them and a more or less equal number saying that they are using aluminium and are very happy. Most are saying they get over 25000 miles on their aluminium sprockets. I would be inclined, after reading all this conflicting opinion, to go for the aluminium PBI Sprockets especially considering that they use 7075-T651 material. I'm not sure but aren't some manufacturers like KTM and Ducati using aluminium as original equipment on some of their models?
 
#33 ·
Update: I too went for 39 rear, from Supersprox, and it really makes the T120 perfect for my use: nothing but good things to say about it.

Also, Supersprox have now listed the 39T for the T120, it matches, no hesitation. Won't go back to stock.
 
#36 ·
Yeah... that little extra RPM in the low end speeds of the first three gears, is what I find missing.
The 39 tooth rear sprocket and later this spring, the CAT bypass, are probably the last two mods to my bike.
I can't fault anything else... even the seat fits my butt and riding position well.
 
#38 ·
I have been keeping an eye on consumption but I can't find anything conclusive about that. It may increase instant consumption a bit but that does not show on the average mileage readings I get.

You are right to wait until the motorcycle is properly broken in and only then change the sprocket.
 
#41 ·
RPM Change

Want to change to 39 tooth also but wanted rpm change between 39 and 41 to make it easier to understand and which to choose. After some research which could be wrong I come up with this. With a 39 tooth you have a little under 5% change or 150 rpm change at 3000 rpm. Remember this is 3000 rpm. With the 41 tooth you over a 9% change. So you have around 285 rpm change at 3000 rpm. The 285 rpm to me and the bike is too much and too much wear and tear on the bike. So I come up with the same answere as every one else. 39 tooth is perfect. I could be wrong here again but trying to make it easier to understand at least for me. Is the Daytona 675 2006 to 2017 going to be right? Cheers
 
#43 ·
On my KZ1000 (not totally stock engine so this is "apples and oranges").... the stock gearing is 32/15= 2.133:1.
Mine is running 35/15=2.33:1 and I can just barely perceive a difference in performance... just barely.
Again I mostly notice it in the first two gears and especially when riding two up.
There is virtually no difference in gas mileage between the two... and I suspect it's very slightly better when two up in the city, using the 35/15 combo.
However, on the KZ1000, when I put my 14 tooth counter shaft sprocket on with the 35 rear.... 35/14=2.5:1___________HOLY HELL!!

2016 T120:
I'll eventually go with the 39 tooth rear also as that seems a good compromise... but I would not be afraid of the 41T if I was just chasing my buddies around in the mountains and such.
Honestly, it's too much work to change these things back and forth for testing... I'll just stick with the one time swap (before wearing it out) to a 39T and be done with it.
 
#45 ·
Hi mate
So after being Not happy with the gear ratio on my T130 that make it rough to ride in the city or low speed, I found 2 option either change the front gear from 17 to 16 ;which make the chain tension almost impossible as the rear wheel is moved far aft on the swing arm... or find a bigger rear sprocket (39 or 40 t) I finally found from French Mecatwin ! A 39t .... the 40t is in production and ready for the summer.
Actually 40t is the max that allow to keep the original chain. It also benefit the handling as the rear wheel is moved fed by 1 or 2 cm which shorten the bike and improve steering ...
Well after 1000km I must recognise that the bike as nothing comparable !!!
Engine is smoother behave much better at low speed, you can ride 3nd gear at 1500rpm, you may even expect to use the 6th gear ...
I guess that 40t will be perfect !!!
For those who are worried with fuel consumption.. I did not notice a difference.
Conclusion : go for 39t or 40f rear sprocket ... you will get a new T120, much enjoyable ... more responsive.
 
#46 ·
Thanks for the information :thumb I am also trying to find a rear sprocket for T120 and this sounds interesting. What is the product number for the Mecatwin sprocket you received? Is it made of aluminum or steel and in which color? What was the price and shipping costs? I visited Mecatwin website and it seems they are closed for the rest of August but I might order one in September.
 
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