It's not for a storm, but I'd like to hear your thoughts

[tony.mon]

For the Tuono you can buy a gear shaft support bearing. I am struggling to understand how it can make a difference. After all, the gearchange shaft is a 12 or so mm diameter steel bar- it can't possibly be bent by the aluminium linkage.

But people say that fitting one improves gearchanging. It already has an up and down quickshifter, which feels good, no false shifts, I can't fault it.

So, as I have a £30 birthday gift from work, I thought I'd get one to see if I can tell the difference.

All I can think of so far is that it will help to minimise damage if I drop it on its lh side, unless the force acts directly along the shaft axis. Any oblique force will benefit from some additional support.

Any ideas as to how, mechanically, it can do anything other than add weight?

[KermitLeFrog]

A waste of money. There is no need for it. As you say the OEM shifting is superb. If you have a left side drop the shift peg on the end of the lever snaps off and is easily replaced with a new one with no damage to anything else.

Sent from my LLD-L31 using Tapatalk

[MK_WF]

Generally spoken any shift mechanism that works with levers and linkage imposes quite some reaction forces on the shaft.
Usually the shaft doesn't have a roller bearing but a simple bronze bush. This will have more friction when under radial force. And to make it worse that involves rather huge portions of stiction.

A good shaft support has a tight fit and a small roller bearing. The reaction forces are now mainly going through that bearing instead of the bronze bush and thus hugely reduce the stiction/friction effects.

On Chinese Pitbikes its a very useful addition not only for easier shifting.
As these crash a lot and the long shaft easily bends it saves you buying new stuff every other trackday.

[sirch345]

Tony, iirc Micky (mik_str) bought one of those for his Carbon Express,

Chris.

[tony.mon]

Thanks. I'm fitting it today, so I'll find out if it feels any better.

[KermitLeFrog]

Thanks. I'm fitting it today, so I'll find out if it feels any better.

I'm not sure how it could feel any better. I suspect (but can't be arsed to check) that the case bearing the shift shaft goes through is a roller bearing and not some shitty pit bike bush. In which case all you will be doing is adding friction (and weight) from the additional bearing and seals. Beware confirmation bias.

[tony.mon]

Well, fitted, and no discernible difference. The standard shaft bearing is also an outrigger, so the racetorx one just added a little extra support even further out nearer the lever at the gearbox end.
I did get two missed downshifts to first, but that's par for the course when downshifting at lower revs, it's perfect at mid to high revs.

The only good point was that I dug out more weight in old chain lube and grit than the weight of the new parts!

The standard bearing on a V4 Aprilia motor is already placed right towards the outer end of the shaft, if it were a design that left a long length of unsupported shaft it might be worthwhile.

Nicely made, though.

[IanB]

The acid test for "will it do any good" is simple; without it fitted, mount a dial gauge first below, and then behind the gear spindle. As long as the lever is tight on the shaft, you can pick up on the lever (if enough shaft isn't available for the probe of the dial gauge).
Change gear with the gear lever as normal. Record any movement on the dial gauge.

If there is little or none, then this is exactly how much this accessory could benefit (assuming it allows no radial movement when fitted).

Ian

[KermitLeFrog]

I don't want to sound like a permanent Cassandra on all of this but what will that prove? The radial movement of the end of the shaft when shifting gear will be very small. A combination of the bending strain (fractions of a micron or less?) plus the slack (if any) in the end bearing/bush. Both of these combined will be negligible. Any possible reduction in this negligible amount will have no effect on the operation of the transmission.

What will probably have a very small effect is the extra friction caused by the additional bearing and seals. But I can't see this being noticeable either until the seals fail and the bearing gets knackered. In essence this is a nicely made piece of bright red bling/tat which in the case of a V4 Aprilia is pointless. This sort of stuff really makes my engineering head hurt.

[tony.mon]

That's what I thought as well, but I had some "bike" money to spend and thought I'd decide for myself whether there was any truth in the occasional rave reviews you see supporting the product.

If the standard-fit outrigger bearing was sloppy it might make a difference, I suppose.

Myth busted, for me, anyway, on that model.


(And yes, I bought the red one, it can stay on until it goes pink!)

[mik_str]

I installed one on my VTR for two reasons: OCMD ('nuff said), and also due to my incremental approach to modding the bike. While its effect could not be expected to be world-changing, it also cannot do any harm. Providing additional support to the protruding section of the sift shaft can only help reduce whatever binding may be present. In my case, it complements the Factory Pro shift kit and attention to setting the right angle of the shift linkage. It all adds up.

So, is it necessary? No. Can it hurt? No.

[sirch345]

Well, fitted, and no discernible difference. The standard shaft bearing is also an outrigger, so the racetorx one just added a little extra support even further out nearer the lever at the gearbox end.
I did get two missed downshifts to first, but that's par for the course when downshifting at lower revs, it's perfect at mid to high revs.

The only good point was that I dug out more weight in old chain lube and grit than the weight of the new parts!

The standard bearing on a V4 Aprilia motor is already placed right towards the outer end of the shaft, if it were a design that left a long length of unsupported shaft it might be worthwhile.

Nicely made, though.

Interesting to hear your opinion Tony
At least you now know with first hand experience

Chris.

[sirch345]

I installed one on my VTR for two reasons: OCMD ('nuff said), and also due to my incremental approach to modding the bike. While its effect could not be expected to be world-changing, it also cannot do any harm. Providing additional support to the protruding section of the sift shaft can only help reduce whatever binding may be present. In my case, it complements the Factory Pro shift kit and attention to setting the right angle of the shift linkage. It all adds up.

So, is it necessary? No. Can it hurt? No.

Chris.

[8541Hawk]

I totally understand trying it out.....I've done my share of "experiments" over the years. On this though I passed as the shift shaft,on a VTR, already rides in a needle bearing as it exits the case. So adding another next to it didn't add up for me.......Though just my opinion and YMMV

[mik_str]

I totally understand trying it out.....I've done my share of "experiments" over the years. On this though I passed as the shift shaft,on a VTR, already rides in a needle bearing as it exits the case. So adding another next to it didn't add up for me.......Though just my opinion and YMMV

I think someone needs an OCMD booster shot, lol