On the importance of cush hubs

85RZwade · December 22, 2019, 09:59:05 AM

Today I want to know how important y'all believe a cushioned sprocket hub to be on a road-going motorcycle. I was reminded of this question by what I believe to be a KTM rear hub in that Motolana swingarm pictured in another thread.
Generally, street bikes have 'em and dirt bikes don't...but my TZ doesn't, and there are scores of dual-sports without them. I've asked a friend who has had plates on a couple of dirt bikes and he has had no problems.
To put a fine point on it, is there concern of long-term wear or damage to the transmission caused by use of a non-cushioned rear hub riding on pavement?
Wade

m in sc · December 22, 2019, 10:16:47 AM

theres a cush in the clutch.

fwiw, i took the cush rubbers out of my euro spec rd400 hub , haven't had an issue. I personally don't believe its necessary

Yamaha 179 · December 22, 2019, 12:04:17 PM

Wade:
I believe in cushioned hubs. So much so that on my TR3 race bike I took the TR rear wheel off and fitted a RD 350 rear wheel. I was racing that bike a lot and the benefits were a larger rim (for a bigger tire) and (in my opinion) increased transmission life.

From the Yamaha point of view the RDs were meant to run thousands of trouble free miles. They actually are good motorcycles. Their race bikes, no matter road race or dirt racers, are meant to have relatively short lives before replacement. The TRs and TZs have cushioned clutch hubs so they get a little shock relief plus they get a lot of routine maintenance that can identify problems early.

Bottom line, if you want to fit a rear wheel with no shock cushions, go for it. You probably won't put enough miles on the bike to over ride the protection in the clutch.
Lyn Garland

oxford · December 22, 2019, 04:53:31 PM

There was a company at one point that was making cush sprockets. I think they may not be around any more

I had looked into them at one point because I was going to use a dual disc xs650 front hub as a rear hub on a rd to get a spoked rear disc with a relatively small hub. I never got on that project and by the time I looked for the sprockets I couldn't find them. Maybe there is something out there now.

sav0r · December 23, 2019, 09:09:19 AM

I googled around for a few minutes. They are made in NZ, the guy who imported them to the U.S. stopped selling them in early 2018.

https://www.motomox.co.nz/shop/show_single_product.php?prod=499

I've closed out my tabs with the info, but the guy selling them in the U.S. claimed 30% better tire life. That is hard to believe.

motodreams · December 23, 2019, 10:30:25 AM

Quote from: Yamaha 179 on December 22, 2019, 12:04:17 PM
Wade:
I believe in cushioned hubs. So much so that on my TR3 race bike I took the TR rear wheel off and fitted a RD 350 rear wheel. I was racing that bike a lot and the benefits were a larger rim (for a bigger tire) and (in my opinion) increased transmission life.

From the Yamaha point of view the RDs were meant to run thousands of trouble free miles. They actually are good motorcycles. Their race bikes, no matter road race or dirt racers, are meant to have relatively short lives before replacement. The TRs and TZs have cushioned clutch hubs so they get a little shock relief plus they get a lot of routine maintenance that can identify problems early.

Bottom line, if you want to fit a rear wheel with no shock cushions, go for it. You probably won't put enough miles on the bike to over ride the protection in the clutch.
Lyn Garland

The bold section is the best statement from Lyn here. These bikes get such little use you won't notice the difference in wear. Built to last for long time from factory. Garage queens today. Some exceptions but few.

oxford · December 23, 2019, 06:58:28 PM

Quote from: sav0r on December 23, 2019, 09:09:19 AM
I googled around for a few minutes. They are made in NZ, the guy who imported them to the U.S. stopped selling them in early 2018.

https://www.motomox.co.nz/shop/show_single_product.php?prod=499

I've closed out my tabs with the info, but the guy selling them in the U.S. claimed 30% better tire life. That is hard to believe.

There must have been more than one place making them. I did some googling and found that the ones I had been looking at was Kush Sprockets out of Australia(?????) and the price was definitely not $300 or I wouldn't have even been entertaining it.

I didn't seem to find a current website for that place though, which may confirm my remembering they went out of business.

Dvsrd · December 23, 2019, 07:35:39 PM

Quote from: oxford on December 22, 2019, 04:53:31 PM
There was a company at one point that was making cush sprockets. I think they may not be around any more

I had looked into them at one point because I was going to use a dual disc xs650 front hub as a rear hub on a rd to get a spoked rear disc with a relatively small hub. I never got on that project and by the time I looked for the sprockets I couldn't find them. Maybe there is something out there now.

Well, the stock XS650 spoke wheel rear hub has no cush drive whatsoever, and a lot of streettracker builders use the stock 19" cast front wheels as rear wheels even on 750 kitted, hopped up XSes. At best a bike like that has 60, maybe 65 hp.

sav0r · December 23, 2019, 10:36:41 PM

Quote from: oxford on December 23, 2019, 06:58:28 PM
Quote from: sav0r on December 23, 2019, 09:09:19 AM
I googled around for a few minutes. They are made in NZ, the guy who imported them to the U.S. stopped selling them in early 2018.

https://www.motomox.co.nz/shop/show_single_product.php?prod=499

I've closed out my tabs with the info, but the guy selling them in the U.S. claimed 30% better tire life. That is hard to believe.

There must have been more than one place making them. I did some googling and found that the ones I had been looking at was Kush Sprockets out of Australia(?????) and the price was definitely not $300 or I wouldn't have even been entertaining it.

I didn't seem to find a current website for that place though, which may confirm my remembering they went out of business.

$300 NZ is like $200 USD. Not sure if that makes a difference to you or not.

Again, I closed all my tabs, but there was mention that the NZ unit was sold in Australia too. The American guy shut his website down almost two years ago, it was like cushdrive.com or something along those lines.

oxford · December 24, 2019, 05:22:39 AM

No, pretty sure it was a different company than the one you found. Here is a picture of what the one I was looking at was

Dvsrd · December 24, 2019, 11:08:25 AM

Looks very similar though, just that the side cover/ring is removed

sav0r · December 24, 2019, 11:26:20 AM

Yeah, that's identical to the on one my link with exception of the annodize.

oxford · December 24, 2019, 12:13:48 PM

Quote from: sav0r on December 24, 2019, 11:26:20 AM
Yeah, that's identical to the on one my link with exception of the annodize.

I looked that link over again, I hadn't seen the additional pictures in the bottom of the page before. They are a similar design with a different means of getting there. It appears that the one in the link uses that bolt on side plate to hold things together.

The one in the picture I posted above had used ball bearings in between the inner and outer sprocket to keep things in alignment

No idea which one would be better in design. The one in the picture I posted does look a little less clunky than the other one. The one in the link may be serviceable?

85RZwade · December 24, 2019, 03:38:34 PM

Fantastic! Answers, opinions and a fun detour into cushioned sprocket land. I didn't know such things existed!
Wade

RdsOnly · December 28, 2019, 05:20:48 PM

Most the engines I have done the RD clutch rubbers are shoot. I have a kit for R5 and rd350's, the big deal is milling the rivets.
RD400 clutch baskets are really hard, have to grind. SO I do not do them any more.

Rear Hub cush can be replaced easily.

Lynn pegged it low mileage usage wont tell on you.

JT

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On the importance of cush hubs