Ohins Rear Spring Numbers Mean What?

[Mike Stewart]

Dudes,

 

The numbers on my Ohlins rear shock spring on my 03 Rosso are 1091-26/85 L262

I am trying to convert this to pounds so I can cross reference this to my 00 V11Sport. Currently I have a 550 lb. spring on my V11Sport which feels way too stiff, I need to know the kg. of the Ohlins so I can do the conversion.

 

Thanks dudes,

Mike

[dlaing]

Sorry, I don't know the answer...But what is your sag with each bike?

I assume all the preload is dialed out of your Penske???

[Baldini]

Mike,

 

My understanding is that the /85 refers to an 85Kg spring.

 

Re spring rates - are 'Kg' & 'N/mm' same, anyone?

 

KB, Wales

[Murray]

262 may refere to the over all wieght in Kilos 2.2lb's to the kilo so your 550lb spring is rated at 250kg's. Although proceded by the L kinda suggests that is the overall length in mm. Is there anything on the Ohlins web site?

[Mike Stewart]

Yes, the spring is an 85 kg. mm. and there is a way to convert it to lbs. in.

A friend of mine did a rough est. last night using a conversion that he made up and it came out to be 475 lb. in. for the stock Ohlins spring. I just do not know if his way of figuring out the conversion is correct. The LE respring and Penske springrate both use 550 lb. in. and both shocks are very, very harsh no matter where the sag is set.

 

Thanks,

Mike

[Baldini]

Mike,

 

Could it be the harshness is caused by the damping rather than the spring? I have a Scura to which I fitted a 100Kg spring in place of the std 85. The spring is great, & shock works pretty good now, but I feel that the high speed compression damping is too stiff, causing harshness over sudden, sharp bumps. I understand this is not adjustable on my shock unless it's dismantled, the external adjuster only affecting low speed damping.

 

KB, Wales

[al_roethlisberger]

Very true, this is often the case, where the compression damping is actually the culprit. Try backing it all the way out, then all the way back in... then start taking compression out a few clicks at a time, ride, adjust, ride... and see if you note an improvement.

 

If not, you may need a new spring and/or high-speed compression valving set on the shocks. If the sag is correct without much preload necessary, the spring rate is probably close.

 

al

[Mike Stewart]

Baldini,

 

I also think the compression dampening is too stiff, I wanted to go to a lighter spring to make sure that was the cause before sending the shock back to have it revalved. The first 2 inches of travel feel fine but after that it is way too stiff. The freeway expansion joints in California will jar the fillings loose from your teeth, and bump you cheeks off the saddle with any slight bump.

 

Mike

[al_roethlisberger]

I thought the Penske had high-speed compression damping adjustability(external) or did you just get the "2 way" adjustable shock?

 

al

[Mike Stewart]

Al,

 

There are only 6 compression settings on the Penske shock. I do not really feel that much difference between them. They use a rotating drum with six different sized orifices to control low speed compression. I think the high speed dampening is shimmed to stiff thus not allowing fluid to blow by on larger bumps.

 

Mike

[Mike Stewart]

I thought the Penske had high-speed compression damping adjustability(external) or did you just get the "2 way" adjustable shock?

 

al

I should of spent the extra money for the fully adjustable Penske shock, but it was $400. dollars more. Everyone said the two way adjustable shock would be fine. I think it is just a tuneing thing...

 

Mike

[al_roethlisberger]

But bottom line, you say that the stock high-speed compression damping on the Ohlins seems good? Overall a good package and ride?

 

al

[dlaing]

If the sag is "right" with the preload minimized, and it still rides like a freight train, we can assume it is the damping, correct?

Your Sachs shock has 50mm of travel to give you ~100mm of wheel travel, so correct sag should be:

Sport

20% 20mm

25% 25mm

30% 30mm

33% 33mm

Touring

Don't ask how I did the math

Divide by 25.4 to get inches.

 

FWIW I believe the spring rates are linear even under preload, but preload throws a wrench into calculating proper spring rate.

So we cannot say that a 550# spring giving 15mm of travel should be replaced by a 275# spring if you wanted 30mm sag.

But you might be able to assume for every pound over the rear axle that it takes to get it to proper sag, you could subtract that from the 550 lbs to find the proper spring rate. But this does not hold true because of the 2:1 ratio, so in fact that weight should be doubled.

So, if adding a 100# wife gets the sag to a good number, than you need a 350# spring.

WARNING: this is all pure speculation based on absolutely no experience. And even the logic behind the speculation may be wrong....

[Mike Stewart]

But bottom line, you say that the stock high-speed compression damping on the Ohlins seems good? Overall a good package and ride?

 

al

Al,

 

The Ohlins on the Rosso is great but the aftermarket Ohlins is different. How different, I don't really know. We will have to compare them when you get yours.

 

Mike

[Lex]

Mike,

 

You wouldn't be the first person to find an aftermarket Ohlins shock set-up with too much compression damping, I've been there myself. My first impression of Ohlins shocks (back in the eighties when they were new to the US market) was very poor, sort of a Swedish Marzocchi. I put one on my bike and it rode like an empty truck and the tire was off the ground half the time in the bumps. Remember we are talking about a big guy, I can't imagine what it would have been like for a rider 100 pounds lighter. A quick re-valve and it was the equal of any shock I've ever used. Don't worry, help should near by. It does kinda' piss you off to pay premium prices for something so badly set-up and then pay more (or at least wait even longer) to have it fixed.

 

Cheers,

 

Lex