Taper Rollers for Swinging Arm

[Duccout]

Many years ago there was a Belgian rider who raced a 450 with a Statchel (not sure of the spelling) 500 single conversion, and I believe that he won the CRMCs Period Two championship on it. Speaking to him at Snetterton all those years ago, he told me that he had converted the swinging arm pivot to taper roller bearings, having found a bearing that fitted the bush housings, and was good enough to give me the part number (long since lost). I never managed to identify the bearing by the part number and the only taper rollers available that small measure 31mm and 34mm, so how did he do it?

[Jordan]

I don't know, but any modification that does away with the standard swing arm spindle design should be treated with suspicion.
On our Ducatis, It is part of the frame. Other cross tubes are far away from the the swing arm.

Needle roller bearings might be what was used?
A Torrington type that has an outer shell/race and crowded rollers might work.
The standard swing arm pin was hardened, so could serve as bearing surface.

[graeme]

Never heard of tapered roller bearings in a single swing arm, but anything is possible.
My 450 Desmo has needle roller bearings in the swing arm.
If I remember correctly, two on each side.
Outer bearing housing, caged needles, inner race. 4 in total.
A new stepped pin was turned up with a threaded section on one side to return the pin size to the larger diameter to lock into the frame clamps.
Two grease nipples, one each side for lubricant.
This has lasted a long time.
Would I do that again ? No, it’s not worth the effort as I don’t think there is any advantage.
I had a nylon / plastic material in a 900 SS long ago that lasted well, I think it was called Lubron?
This was use instead of the bronze bushes and didn’t need greasing.

Graeme

[Jon Pegler]

Having owned a number of Nortons back in the 1970s, all fitted with Metalastic bushes in the swinging arms, I was always happy that they were entirely maintenance free, and the bikes handled impeccably.
When I came to fitting some replacement swinging arm bearings into a 450 Mark 3 back in the 1980s I thought I would try a metalastic conversion.
It worked fine, and is still working fine 35 years later.
Would I do it again? No. As Graeme says, it's not worth the effort.
The bushes needed turning down slightly to fit into the swinging arm.
A spacer was needed between the bushes in the swinging arm and a spindle was needed, which was carried on outrigger bushes in the frame.
As an exercise it was worth doing, especially when I was accumulating a high mileage on the 450, but now the 450, together with all the other Ducati singles I have only go out occasionally, so I wouldn't bother, just sticking to the standard bronze or nylon bushes.
I would guess that fitting either taper rollers or needle roller bearings into a Strada/Forza frame would be quite a challenge.
Not impossible, but difficult.

Jon

[Duccout]

The guy who had the taper rollers had fitted aluminium blocks into the swinging arm pin clamps each side, bored for the central threaded shaft to come through, with nuts on each side to adjust the taper rollers, and it all looked very professional. I'm guessing that he used 31 mm diameter bearings and bushed the housings.

I must admit that I am (so far) impressed with the plastic bushes, they are far easier to ream than bronze and any misalignment will not be so much of a problem to deal with. If I have to replace the bushes on my 900 sometime, I may try plastic and invest in a piloted reamer. If they only last 10000 miles that is not such a problem if they are easy to replace.

[themoudie]

Aye Colin,

Have a read of this web page: Swing_arm_bearing_type_discussion

Good health, Bill

[Duccout]

Thanks Bill, that's a good read.


Colin

[LaceyDucati]

Colin

I converted my race and road bikes to ball races in the swingarm back in the early 90's, I picked up the idea/concept from Pat Townsend's conversion. Owning a Guzzi V50 at the time, I had also noted all small block Guzzi twins used 2 x 6202 bearings for the S/A bearings. I therefore figured they would be more than adequate for a lighter Ducati single. I used angular thrust bearings in my widecase road bike and std 6202 bearings in my narrowcase race bike.

I never had any issues in doing so and various UK Ducati single racers I was involved with also had copies of the same conversion. All of Nigel Palmer's and Doug Snow's race bikes ran on 2 x 6202 bearings. There is a taper roller bearing the same size which I did consider using, but the ball races proved perfectly adequate. All the conversions were ad hoc engineering jobs, not straightforward replacements. Replacing bearings thereafter is a quick simple job compared with replacing bushes. Mind you, all these years later none have needed replacement! It's not for everyone, but for me I found the imperfections of the original bush arrangement at it's best less than ideal. That said I would probably stick to the standard set up for a standard/original bike.

Sounds like the Belgium racer you met had a similar conversion, I think he sold that bike through our website some years ago, the details mention it.

https://www.laceyducati.com/ducati-part ... -1107.html

Regards Nigel

[Duccout]

Hi Nigel,

Yes, that is the bike, quite a bit changed from when I remember seeing it, but I do remember that it was Roy Gillard who fitted the 500 conversion, which was sold by TGA. The bike used to be painted in Bianchi Celeste, and very pretty it was too.

I think that it was Roy Gillard who told me that he ran on Castrol R, but one year he switched to a modern oil and wore out the Nova box, so switched back to R. Probably coincidence, but who knows, that's a lot of extra torque through those tiny gears!

Thank you for posting the details,

Colin