Triumph Rat Motorcycle Forums banner

1 - 12 of 12 Posts

·
Registered
Joined
·
2,732 Posts
Discussion Starter #1 (Edited)
I ended up using SAE 30wt non-detergent oil in the front forks of my 66 TR6R. I got the equivalent ISO to SAE viscosity from the Amsoil site for using hydraulic oil. ISO32=SAE10wt ISO46=SAE20wt ISO68=SAE30wt ISO 100=30/40w !SO150=40w
http://www.amsoilinternational.com/viscosity.aspx
Bob
 

·
Registered
Joined
·
2,732 Posts
Discussion Starter #4 (Edited)
50wt non detergent

I've used 50 monograde engine oil in a '66 front end and liked it.
All I could find at the 2nd local auto parts store I tried was straight 30wt, which I use for break-in oil. The only hydraulic oil was 32. I will try to find ISO 100/150 or SAE 40 equivalent. No big rush, it handles fine. The handbook recommended a range of 30, 40, and 50wt. I suspect it had much lighter oil in it. I did change to progressive springs. I run much lighter oil in my disc-brake front ends. Bob
 

·
Registered
Joined
·
5,438 Posts
I've always used ATF in Triumph forks, internal or external spring types. I've never heard of using 30 or 50 w in them. I would have thought that would result in a really harsh ride. Most bikes are very sensitive to fork oil viscosity. ATF is approximately 10 w. a change to 15 w in my Harley Showa forks turns them from a little soft to very stiff.
 

·
Registered
Joined
·
304 Posts
Might it be the case the the forks fitted to pre-oif Triumphs work better with thicker oil and those on the oif T120 and T140s work better with thinner grades?

The workshop manual for my Daytona (same forks as pre OIF T120, I think) specifies SAE30 for summer and SAE 20w for winter.
 

·
Registered
Joined
·
304 Posts
Does the w after the SAE grade mean that oil is specially fomulated for winter use?

I'm talking about monograde oils here, for example see my post above.

If so would a 20w/30 multigrade be ideal for all year round use in my forks? I'm currently using SAE30 fork oil.
 

·
Registered
Joined
·
2,732 Posts
Discussion Starter #8
fork oil

Does the w after the SAE grade mean that oil is specially fomulated for winter use?

I'm talking about monograde oils here, for example see my post above.

If so would a 20w/30 multigrade be ideal for all year round use in my forks? I'm currently using SAE30 fork oil.
The w is for winter in multigrade oils. I do use ATF in my OIF bikes and Trident with a disc-brake front end. I tried to find non-detergent oil so it would not foam. I got a reply from Advance Auto Parts: their house brand straight weight oil is detergent. Bob
 

·
Registered
Joined
·
5,438 Posts
Use whatever feels right. I was just a little surprised that we are using anything from 10w to 50 w in the same forks and everyone is pleased with their choice. Obviously you can alter the damping with a change in viscosity. Apparently the forks are not real sensitive to viscosity changes, probably due to the fairly primitive valving. As I've said, even a 5 w change in my Ducati or Harley would be an extreme change. When I started riding Triumphs it was common to use ATF in forks, it worked fine, it's cheap , and I always have it on hand. Of course, when I started riding Triumphs we had to watch out for Dinosaurs crossing the road.
 

·
Registered
Joined
·
2,732 Posts
Discussion Starter #11
fork oil

Well halleleuyah. Oreilley's lists 30ND and 40ND non-detergent oils. I'll probably need to special order it. Why is this stuff rare as hen's teeth? Their site was down yesterday. I wasted a lot of time looking. Everybody has the very light weight 5,7, 10wt oils for new Harleys etc and nothing else. Bob
 
1 - 12 of 12 Posts
Top