[Kyleinator]

Hello all,

I have a 2013+ Daytona 675R and currently the bike is running stock gearing. The bike is primarily used for the track. I just switched my rear tire from the stock 180/55 to a 180/60 and now my gearing is way too tall. Do any racers recommend a good starting point? Seams reducing sprocket sizes will help with weight so maybe 14f 46r would be a good starting point. What do you all run on your track bikes?

 

[Far Canal]

Gearing is entirely dependent on the type of tracks you ride and how fast you are. Try 15/47 or 14/44 which is pretty much the same ratio but shorter in the swingarm and will therefor tip in quicker.

 

[Kyleinator]

I believe my stock gearing on my 2017 Daytona is 15/47 unless I'm mistaken. The taller rear makes my gearing taller and since it's a heavier tire I'm thinking I should gear maybe a tooth or two shorter than stock. You bring up more questions though. The 180/60 is taller which raises my rear ride height which should increase tip in. This would be beneficial as I've noticed myself really fighting the bike to initiate turns while on throttle. I noticed my Daytona has the rear wheel more towards the center of the swingarm and was told on a previous bike that having it closer to the front giving me a shorter wheel base might be a good idea as it should help turn in. Is it a general rule of thumb to keep the wheel base on the shorter side?

 

[ducdiver]

On my 06 with a 180/60 Pirelli I go up two teeth on the rear at The Ridge, short straight, helps keep the rpm up, and more gear choices. Keep it stock at Pacific due to the long straight away length. Next year at my local track I'm going to try down one in the front and up 2 in the rear. My local is basically a glorified cart track and it's really tight, bugger all for straights, all about the corners. I took a few mill back out of the rear to keep it happy on the brakes and I don't like it too twitchy on tip in. As long as I get hanging off properly my big ass will get any bike turn. All about trial and error to find a setup that makes me feel confident. Not necessarily faster but confident.

 

[manxkiwi]

If you want to maintain stockish geometry, drop the forks 9-10mm down through the triples when running a 60.

 

[Kyleinator]

I mostly ride Buttonwillow which with stock gearing and stock rear tire I'd click into 5th for a split second at the end of the main straight. I'd also have an awkward 3 to 4 shift before having to shift back down to 3rd. If my gearing was a pinch shorter I'd be in 4th a little longer in that section and in 5th a little longer on the main straight

 

[ducdiver]

Going +2 in the rear will get you into the top of the gear box faster but it's not too big of a jump.

 

[Kyleinator]

So does -1f -1r seam like a decent idea to keep sprockets smaller? From my understanding that should be very similar to 15/49. That would put me from 15/47 stock to 14/46 with the bigger rear tire. This should shorten my final drive over the stock configuration (before tire and gear change) . I'm just curious if that configuration makes sense. That combined with a 520 conversation should eliminate some unsprung and drivetrain weight.

 

[Paulo666]

I also went 520 with 15/49 gearing but didn’t like it at Thunderhill East. It’s a big track so constantly shifting. It’s fast out of corners but you top out really quick also. I went back to oem for T-Hill East. So much better for me. Sonoma or Buttonwillow and T-Hill West would be good with 15/49 I think. Even 15/48 in between could be good. Play around with it and see which you prefer.

 

[Kyleinator]

I also went 520 with 15/49 gearing but didn’t like it at Thunderhill East. It’s a big track so constantly shifting. It’s fast out of corners but you top out really quick also. I went back to oem for T-Hill East. So much better for me. Sonoma or Buttonwillow and T-Hill West would be good with 15/49 I think. Even 15/48 in between could be good. Play around with it and see which you prefer.

Do you have a 180/60 rear tire or 180/55? I am planning a Thunderhill East day this year as well. Maybe a Chuckwalla as well.

 

[Paulo666]

Yes I’m using Metzler TD race slick 180/60. Let me know when your going to THill and which track org.

 

[Kyleinator]

That's such a nice bike I still need to paint mine... (Belly pan and track tail isn't installed in the picture 🤣) . I'll definitely let you know when I'm up there I think there was a day early Feb TH East with Pacific Track Time we were thinking of. We're just worried about the weather, never been to NorCal in February before and it would suck to get rained out.

Is there a benefit to using the same ratios but smaller gears? For example a 15/47 vs 14/44 which are almost identical. Or should I just stick with the 15 front?

 

[Paulo666]

I don’t know anyone who uses a 14 in the front. I think it would be to torquey/jerky and to much strain on the chain. Just do a 520 conversion with 15/49. I would change the back and not the front. I don’t do track days too early in the year. February and March is still cold to me and possible rained out day. I heard there were a lot of crashes last year. I wait till the track heats up. I snowboard during the winter. Track days summer. So I have a 47 and 49. Would like to pick up a 48 also. I have DID chain with Renthal sprockets 520.

Looks like you have the Moto2 fairings style?

 

[Far Canal]

I run 14/44 and it's not jerky/twitchy at all, but has a much quicker turn because of the shorter swingarm. FWIW I am a B grade racer and my lap times are within a second of the lap records at my local tracks.

 

[Dan_the_drifter]

Lovely looking bike @Paulo666 ! I'm in the UK but have literally just gone from a 15T to a 14T front sprocket on my 13+ 675 Daytona for the same reason, so I'm running 14/47 with stock length 525 chain and jumping up to a 180 60 tyre, obviously not being at the same tracks its difficult to say, from the online calculators I looked at, just dropping 1T on the front will still gain a smidge of acceleration over stock even with the 60 rear tyre but also allows the same length chain so you can go back to a 15T front if you want/need to (I might do this when using wets as my wet tyres are still 55 profile) very interested to see how you get on.

Here's a link to the thread I put up encase it's of any use, first vid I give a brief overview. Click me

I don't actually know anyone else who has first hand experience on our exact bike in my small track day/friends group doing the same so interested to hear what you think, especially if you get out on track before me!

Also note when comparing to other 675's the earlier bikes are slightly different geared from stock so can confuse things, the same gearing on ours would be even shorter as they start out with a 16T on the front rather than 15T as far as I'm aware.

 

[Paulo666]

I run 14/44 and it's not jerky/twitchy at all, but has a much quicker turn because of the shorter swingarm.

That’s great. So your bike must spin up really fast right? I saw your bike build and looks pretty nice. I’m not racing but only doing track days. I personally like the 15 and want to try a 15/48 at my local track.

 

[Kyleinator]

Paulo666 - Well this is a great year to be into snowboarding in California! Lots of snow! I definitely want to grab a 520 conversion. Yeah I ended up getting a Moto2 fairing kit. I'll have to snap pictures with the full kit mounted. Once I get it painted it should look nice!

Far Canal -14/44 is basically stock final drive ratio. Did you choose those sizes for less rotating mass? What rear tire size do you use Far Canal?

 

[Far Canal]

My bike is a 2nd gen so 14/44 is more like -1/+2 or 15/47. It was suggested to me by my mechanic for less rotational mass and quicker turn in. I use a 180/60 Pirelli.

 

[Kyleinator]

My bike is a 2nd gen so 14/44 is more like -1/+2 or 15/47. It was suggested to me by my mechanic for less rotational mass and quicker turn in. I use a 180/60 Pirelli.

Okay so that's good to know 14t front with a smaller rear sprocket is a thing. It made sense due to the less mass. So you don't feel like 14/44 is too tall of a ratio with the larger 180/60? That's why I was thinking like a 14/46 to keep it closer to stock. Do you have your rear wheel as forward as you can get it in your swingarm or do you have it more centered?

 

[Far Canal]

Okay so that's good to know 14t front with a smaller rear sprocket is a thing. It made sense due to the less mass. So you don't feel like 14/44 is too tall of a ratio with the larger 180/60? That's why I was thinking like a 14/46 to keep it closer to stock. Do you have your rear wheel as forward as you can get it in your swingarm or do you have it more centered?

The gearing works for me, at my speed, with my suspension set-up and for the tracks I ride. Less mass is not the fundamental reason and it's as much personal preference as it is practical. (K Tech 35DDS Pro rear shock and K Tech 20DDS fork cartridge kit).
Yes, the swingarm is as far forward as it can go. I can't remember how many chain links but I can check next week when I get the bike back from my mechanic if you want.
FWIW I have 3 675's and a 765, all with different set-ups to match the engine and suspension mods. One is a Supersport engine to meet my local race regs, the other stock and the 3rd 675 and the 765 are World Supersport spec.