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Makes And Models => Zero Motorcycles Forum | 2013+ => Topic started by: biolife on May 06, 2014, 05:45:58 AM
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Any reason why it wouldn't work?
http://www.zeromotorcycles.com/shop/index.php?main_page=product_info&cPath=15_6&products_id=182&zenid=ht5dhkopu5pttsu97nre47unl0 (http://www.zeromotorcycles.com/shop/index.php?main_page=product_info&cPath=15_6&products_id=182&zenid=ht5dhkopu5pttsu97nre47unl0)
It shows that it's officially only compatible with the S and DS, not the SR. I notice that the SR has a 30 tooth sprocket, whereas the S uses a 28 tooth sprocket.
For someone who drives primarily (like 98%) in the city and lives in a place where most highways have a posted speed limit of 80-90km/h (50-55mph), I don't really see much need to ever maintain a speed any higher than 100km/h (60mph), though based on my calculations (which are entirely assuming the ratios in the SR would result in similar adjustments in speed/torque when reducing the size of the sprocket like in the S), I'd still have a max sustained speed of about 120km/h (72mph).
Any reason why the 25T sprocket won't fit the Zero SR, and are there any other things that I'm overlooking while pondering this potential future modification?
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Some thoughts:
- you might exceed the torque limitations of the belt (or other drive train components)
- you might lose some highway range (but possibly gain city range)
- you might experience some unexpected weight transfer to the rear wheel, possibly as much as 100%
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Same question here. I am seriously considering an S or SR right now. I could see some safety issues but if you have experience on a sport bike, I'm sure you'll be ok. Besides, if you don't need to go 80+ mph, why wouldn't you buy this $30 part!?! You can obviously configure the bike for less power. The info I was given by the dealership is that it should fit. I am waiting for official word from their Zero contact.
First post BTW :)
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I decided to go ahead and email Zero anyway, since I figured they would know best. Here's what Ryan from Zero says:
The hi-torque physically will fit the SR. We have used this set up on a few of our race bikes but don’t have not done any true evaluations to go from. Your launch speed would increase, mostly from 30 to 80 but you would probably top out at 80-85 mph. The other issue I would be concerned with is belt tension. The SR requires a tighter belt spec. than the S/DS. I have seen teeth ripped from belts that were not correctly tensioned. I don’t know if the swing arm will allow the axle to slide back enough to tension the belt properly. Sorry I don’t have any hard answers for you, it would be a true experiment on your part.
Doesn't sound like there are any real issues regarding the drive train components outside of the belt, so it's probably worth ordering the $30 sprocket and giving it a try. I should probably order another belt with it, just to be sure... :P
I'll probably try this some time in the next few weeks, since I'll be moving into a new place with a proper garage that should make tinkering easier. Will report back with how it goes!
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Keep us in the loop!
I'm really curious about replacing mine too. More acceleration would be nice.
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If I pull the trigger on a Zero, I will definitely give it a go. I personally don't plan to ride hard enough to cause any additional stress on a daily basis. Just can't see not spending $30 for " _____" (not sure how to fill in the blank until I ride it. was thinking "optional ridiculousness").
Oh, and don't expect Zero to recommend this mod. They aren't stupid.
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@krash, if you don't plan on riding hard, why bother downgearing?
Why not order a 28 tooth sprocket as used on the S. It would give you an intermediate option. I planned to do this on the SR if I ever justify buying one to myself. I have downgeared every ICE bike i have owned because the speed limit here is 40mph. It makes alot of sense.
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I will ride hard from time to time but 90% of my riding will be commuting to work and around town with only short trips on the highway.
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Ordered my SR today! ;D
Also bought the front sprocket but will wait to install after I feel the bike out. When the dealer asked about the sprocket, Zero person asked "Why?"
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Ok, so my 25T front sprocket is still sitting on my workbench. Anyone done this yet on an SR? My main concern is range/efficiency. An ICE would definitely suffer from a change in gearing but a variable speed electric motor is different.
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An ICE would definitely suffer from a change in gearing but a variable speed electric motor is different.
As I understand it, that's exactly right. The motor will turn somewhat faster at any given road speed, which will result in SLIGHTLY more bearing friction, and maybe SLIGHTLY lower efficiency from the controller, but you probably won't even be able to detect those things.
That said, I can't for the life of me understand why you'd want to give up what little top speed the SR has for even more torque than this monster already puts out. I think Zero did an excellent job gearing this bike.
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To accelerate faster, Duh :)
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During the month I've had my SR, it has spent VERY little time any where near full-throttle. I've seen triple digits on the speedometer [MPH] a few times, and am grateful for the ability to keep up with 75+ MPH traffic on my commute, with plenty of acceleration available even then. I wouldn't trade the ability to exceed 85MPH without red-lining the motor for belt-snapping drag-racing performance... but that's just me!
8)
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We're talking about going from 100 top end to 90 top end. It's $30 and even if you need to buy the stock sprocket to put it back to factory, its still $30! :)
Edit: the SR with 25T sprocket should max at 86mph without programming.
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To accelerate faster, Duh :)
Or just smoke the rear tire faster.
Hey, whatever floats your boat. Like I said, I just can't imagine giving up top end for bottom end, on a bike that can already leave a Tesla, a Ferrari or a Hayabusa for dead in the road. Just seems a little heavy on the overkill to me.
Speaking of bottom end, though, does it seem to anybody else like Zero's "softened" the bottom end a bit? A 407-lb bike with 106 ft-lbs of torque should be unable to accelerate from a dead stop at full throttle without going up in smoke or pulling the front wheel off the ground in a very powerful way. And in the Brammo vs Zero comparison that was just recently posted, it was said that the two bikes pretty much pull together until 20-30 mph, at which point the Zero pulls away. I'm pretty convinced that Zero has limited the torque available at very low speeds to keep people from getting themselves in trouble launching at full throttle. I'm not really concerned about it, as I keep saying the bike has PLENTY of torque for me, I'm just curious.
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Yes it is limited, possibly to spare the belt or the motor.
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Has anyone here actually installed a 25T or 28T sprocket on an SR?
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I believe that Harlan's "Big Blue" which is a 2013 with Size 6 controller (Basically an SR) uses a 28tooth sprocket. The Pikes Peak S's (Jeremiah, and Ted, and maybe Brandon's) had size 6s in them for some time and had 25T on them for some of that.
Using 25T on an SR is very much not recommended, the small sprocket and high torque will significantly reduce the life of the belt, and it could break without any signs of weakening.
-ryan
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But, it only puts out high torque when you twist the throttle. You could always ride in custom mode with 80% torque.
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Why would you install a 25T sprocket then limit torque to 80%?
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For daily riding. Switch to sport to have some fun.
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Is it just me or has a thread that had a simple purpose turned completely stupid?
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krash, just install the thing and report back. Everyone would love to see your before and after numbers. I'd also like to see a video of you pulling the front wheel off the ground :)
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I was waiting on 2 things:
1) To hear from someone else that has done it (25T or 28T on SR)
2) Figure out how to reprogram the 2014 speedometer. This mod will show 20+% higher than true speed.
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2) Figure out how to reprogram the 2014 speedometer. This mod will show 20+% higher than true speed.
Will it? The motor speed will increase but is the speedo based on motor speed? That would be very weird -- every vehicle I know of uses wheel speed to calculate road speed.
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http://electricmotorcycleforum.com/boards/index.php?topic=3722.msg22075#msg22075 (http://electricmotorcycleforum.com/boards/index.php?topic=3722.msg22075#msg22075)
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http://electricmotorcycleforum.com/boards/index.php?topic=3722.msg22075#msg22075 (http://electricmotorcycleforum.com/boards/index.php?topic=3722.msg22075#msg22075)
I stand corrected. It's a brave new world out there.
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I have installed a Kenda cruiser 671 of 140 x 70 x 17 today on my 2012 S
The tire clearance from the join between the two legs of the swing arm was less than 1/8".. I just hammered a bit this tube link on the swing arm by about 1/4" and the tire have run fully free now even at 140kmh.
This new tire raise the max speed by 4% !!
Doc
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Heavy.
https://www.youtube.com/watch?v=lfnAb11wKQc (https://www.youtube.com/watch?v=lfnAb11wKQc)
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I've been laughing for 10 minutes! Watched it 3 times.
EDIT: We need a 26T to get us to 88 mph!!!!
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You didn't see bttf movies ?
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Just change the sprocket man! If you don't like it you can change it back.
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This topic resurfaced so I thought I would post that I have not installed my sprocket. I'm concerned about the stock tires and I'm not sure if anyone knows how to code the speedometer for a 2014 SR.
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This topic resurfaced so I thought I would post that I have not installed my sprocket. I'm concerned about the stock tires and I'm not sure if anyone knows how to code the speedometer for a 2014 SR.
As Doug S said earlier in the thread, I can't fathom wanting more torque than the bike already puts out. As a new SR owner I am blown away by the bike's acceleration on every ride - it is so quick that there are very few situations where I can actually go to the throttle-stop, and then only briefly. I have owned some very fast vehicles and have always wanted just a little more thrust - not with the Zero. It scares me as it is. But, different strokes. If you do the mod and it is noticeably quicker I would love to read a ride report. Are you targeting Veyron acceleration?
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Just because you got it doesn't mean you use it every time you go. Range and top speed isn't an issue for me. It's personal. The SR has no top end anyway. 100 mph is mid range. It's a low end beast.
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I've never been able to get the front wheel off the ground on the Zero SR. I was thinking that a high gear torque would aid that. Of course the Zero already has a great amount of torque, but it also has a top speed way higher than I ever want to use. So to me this mod makes a lot of sense.
I would love to encourage someone who's up for it to give it a go.
krash7172 and biolife - you obviously are curious to how this would work. I say just do the mod, test it. Film it. If you don't like it (which I doubt), just put the stock gear back. And user dgh853, you're the track racing guy on the forum, you're curious and great at doing mods.
I would do it myself but it's winter here with snow - and my 2015 haven't arrived yet.
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Just got an email from my dealer. Who tells me the cheif european technician for Zero says it's ok to change the gear. I can even order my new 2015 SR delivered with the higher torque gearing from the dealer.
I asked about details, I hope he comes back with more.
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You can always try the 28T sprocket. I would have ordered that if I knew it was an option when I purchased the bike.
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We don't recommend changing this sprocket on the Zero SR for two reasons. First, the higher torque has resulted in broken belts for some customers. Second, your odometer and speedometer won't read correctly without further adjustment. I know of some customers that do this for racing purposes only but are willing to bear the extra costs that results because the issues it can cause are not covered by your warranty.
Regards,
aaronzeromoto
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I have recently changed to an equivalent high torque / low gear option by way of a chain drive running a 15 tooth front and 80 tooth rear. This is very close to the same gearing as a 25 tooth and 132 belt drive.
I had been told of the risk of belt snapping so the chain drive was the only safe option to my mind until Zero move to wider (and stronger belts).
So what's it like and will it wheelie?
The acceleration is a small but noticeable improvement over stock and the bike will wheelie in certain circumstances - uphill and sitting back on the seat it will come up a little around 40kph. Top speed is now about 137kph (85mph).
The Sava MC50 Racer 140/70 17 tire I'm running is certainly capable of handling the extra power in a straight line, whether there is enough power to get real wheel slides when leaned over on the track I'm yet to test but I doubt it as the torque drops off from 3000rpm to 6000rpm (latter is max rpm). Also, 135kph on the track is way too slow for anything but a short tight race circuit so will likely switch back to the 185kph (58 toot rear sprocket) setup when I'm next at the track.
For those who are keen I would follow Zero's suggestion and not use the 25 tooth with the belt drive. I think the chain drive route is the way to go and gives more flexibility in gear selection. A friend of mine has a CNC machine and could make custom sprocket sizes to suit your needs - you'd need to replace the front sprocket with a taperlock setup or similar as we have done.
Dave
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Sweet :) Did you calibrate the speedo?
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Not yet, you need a custom cable that connects to the MBB (Main Bike Board) to make that change. I believe it can be done by your dealer if desired. I'm using a Garmin bicycle GPS to give me accurate speed readings ATM.
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Do you need to buy 2 chains and link them together to get enough length?
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Do you need to buy 2 chains and link them together to get enough length?
One chain will be enough for 15 x 80 combination but it needs to be at least 135 links.
I used an RK 428SO chain with 136 links and I took out a pair of links to keep the wheelbase short. 136 links would work too but you'd need to pull the wheel back further.
I think you should consider the ZERO FX CHAIN KIT. If it matches the stock gearing on the FX then this is equivalent to the 25/132 combination people are looking at for the SR.
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That sprocket looks really nice! I've had good results using HD 428 chain on my ICE bikes, it's light and low-drag.
The FX chain kit (520) has 12T front / 65T rear sprockets, for a 5.42:1 ratio (about 2.6% lower than 25/132). I think they may have done this to minimize changes in RW torque and speedo readings when using knobbies, which are generally larger in diameter than the OEM low-profile IRC.
I've been looking at all-steel-wear-points chain options to get the front wheel up easier on my FX, and it seems the easiest route might be 530 chain, which has the same dimensions as ANSI #50. Martin makes 1"-shaft 1" wide #50 front sprockets from 10T to 23T, and I believe both SuperSprox and Sidewinder make custom 530 hybrid rear sprockets up to 70T (I'm waiting to hear back from both).
The '04-'15 KTM 85SX rear wheel appears to use an identical sprocket mounting setup to my FX (four M8 holes in 132mm dia. circle, 110mm center hole) which made spec'ing the custom sprockets a lot easier.
Ray
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Although not an SR, I ordered by 2014 DS with the 25T drive sprocket installed.
The mechanic indicated he had to remove the motor from the bike and heat the shaft to remove the stock sprocket, which was destroyed in the process. It was an hour, or so, of work, and the mechanic recalibrated the speedometer at my 600 mile inspection. Interestingly, my Zero iPhone app now reads a different speed than the bike speedometer.
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We don't recommend changing this sprocket on the Zero SR for two reasons. First, the higher torque has resulted in broken belts for some customers. Second, your odometer and speedometer won't read correctly without further adjustment. I know of some customers that do this for racing purposes only but are willing to bear the extra costs that results because the issues it can cause are not covered by your warranty.
Regards,
aaronzeromoto
That suggests to me that the SR should be fitted with a stronger belt from the factory, if a relatively small change (less than 10%) results in broken belts.
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I ordered a 28t sprocket and it took the dealer 2,5 hours to fit it. They told me that they removed the rear axle to have enough space.
Is it faster? Well, at least it feels faster ;D The mechanic told me that he was able to wheelie (I didn't try as I don't like that). Next day's I'll try to measure some numbers with an app on the phone.