Help.. Installing ohlins axle hits muffler???
Road Captain
Joined: Jun 2006
Posts: 548
Likes: 7
From: Pittsburgh, PA
In the case of a '09 or '10 bike this might not be such a hot idea. If you go any shorter than 247mm center to center on the shock mounting bolts the swingarm can hit the frame on the left side at full compression. I just verified it on my bike. Keep in mind these are cast parts so size and shape can vary. A thicker piece will hit sooner. The extended length of the shock with the ride height adjuster screwed in all the way with the blue nut in place is 324mm. The stroke is 77mm so 324-77=247mm. On my bike it hits at 247mm. If I were to take the nut out it would be 5mm shorter which would cause it to hit sooner. I think Ohlins knew what they were doing when they set the specs. Most of the time its best not to second guess them 
Marc
Marc
I'll keep my eye on it.......... But I did discuss this with Howard before doing the mod and he said it would work fine. Ohlins does in fact now offer (through Howard) a 12" version of this model ( which is a #3-3, I think) It is the same shock with a solid, non adjustable eye on the bottom that is the same length that I ended up with in doing the mod. There is also a formula that Howard uses for maximum compression ( I can't remember the thread it's in) and according to that formula I still have 1/4" clearance with full compression.
Road Captain
Joined: Nov 2007
Posts: 554
Likes: 0
From: SoCal
I don't know if Howard had a '09 bike available to try it on. Probably not. Normally if they supply a shorter shock they will shorten the shaft within the stroke area. In that way the wheel starts out 1" higher but ends up in the same place when fully compressed. That's how a Street Glide shock is compared to an Ultra as an example. If Howard and you were considering the safety in shortening the shaft in regards to the tire hitting the fender you guys would be looking in the entirely wrong place. It is impossible for the tire to hit the top of the inner fender. I tried it on mine today and there is over 1" of clearance between the tire and the fender when the wheel stops due to the swingarm hitting the frame. In other words, tire clearance is not a factor and if Howard was using that as a criteria it would mean he didn't have a '09 to check out or he would have known better. If you have a '09 you might want to remove the l/s cover and take a look where the swingarm meets the end of the frame where the rear section bolts on. That's where it hits. Couldn't hurt to take a peek.
Marc
Marc
Thanks Marc,
I'll keep my eye on it.......... But I did discuss this with Howard before doing the mod and he said it would work fine. Ohlins does in fact now offer (through Howard) a 12" version of this model ( which is a #3-3, I think) It is the same shock with a solid, non adjustable eye on the bottom that is the same length that I ended up with in doing the mod. There is also a formula that Howard uses for maximum compression ( I can't remember the thread it's in) and according to that formula I still have 1/4" clearance with full compression.
I'll keep my eye on it.......... But I did discuss this with Howard before doing the mod and he said it would work fine. Ohlins does in fact now offer (through Howard) a 12" version of this model ( which is a #3-3, I think) It is the same shock with a solid, non adjustable eye on the bottom that is the same length that I ended up with in doing the mod. There is also a formula that Howard uses for maximum compression ( I can't remember the thread it's in) and according to that formula I still have 1/4" clearance with full compression.
Road Captain
Joined: Nov 2007
Posts: 554
Likes: 0
From: SoCal
I just took one of the Ohlins' springs off and measured the stroke. The specs call for 77mm stroke but with the rubber bump stop in there you'd never quite get that much. Hopefully with the the bump stop in there you might not ever hit. The only way to know for sure would be to remove both shocks, remove the spring from one of them and reinstall that shock on the l/s. You could then lower the bike down until the shock bottomed and then look and see if there is any clearance left between the swingarm and the frame. It won't completely compress the bump stop to the extent that it would be after hitting a big bump but at least you'll get an idea of how close it is. It looks like you have 220mm springs so you might not be able to get it off. I have the original HD909 length spring of 200mm and it comes off easily. I would check it for you but my shock hasn't been modified so it wouldn't tell us much. Let me know if I can help at all.
Marc
Marc
Road Captain
Joined: Jun 2006
Posts: 548
Likes: 7
From: Pittsburgh, PA
Ah, I see what you're talknig about now Marc,
Not the fender clearance, but the swing arm travel. I'm going to call or email Howard and see if he's tested the new swing arm and frame. I don't know if he's aware of any the differrences. I'm not sure what length springs are on mine. I really don't want to struggle with taking the springs off, LOL. I suppose I could put the bike on the jack, get an exact measurement eye to eye, then remove the shocks , lower the bike until the swing arm hits the frame and measure the difference? I've only got about 1200 miles on the bike since I put them on in the fall. I maybe have bottomed out once or twice in some deep pot holes but it has NEVER felt as hard and jarring as the stockers. I'm solo 99% of the time. I'll let you know what Howard says after talking with him.
Not the fender clearance, but the swing arm travel. I'm going to call or email Howard and see if he's tested the new swing arm and frame. I don't know if he's aware of any the differrences. I'm not sure what length springs are on mine. I really don't want to struggle with taking the springs off, LOL. I suppose I could put the bike on the jack, get an exact measurement eye to eye, then remove the shocks , lower the bike until the swing arm hits the frame and measure the difference? I've only got about 1200 miles on the bike since I put them on in the fall. I maybe have bottomed out once or twice in some deep pot holes but it has NEVER felt as hard and jarring as the stockers. I'm solo 99% of the time. I'll let you know what Howard says after talking with him.
Former Sponsor
Joined: Apr 2007
Posts: 5,360
Likes: 453
From: Davie, FL
clarification
I received an e-Mail from SG Larry & also Marc.
- I asked Marc to send me a photo of the swing arm hitting and where it hits.
- I have never tried or would try to remove the check nut. The shocks are shipped with check nuts installed.
- After I get back from Daytona I will look into this. I have too much work to do until than trying to leave on time.
Road Captain
Joined: Jun 2006
Posts: 548
Likes: 7
From: Pittsburgh, PA
I got a a chance to check and take "rough" measurements and how and where the swing arm will contact the frame. Mine contact at around 8-12/16 eye to eye with the socks removed (maybe like 223mm?) Even with mods to the lower eye, I don't think I'm even near hitting the frame when they are fully compressed. Spoke with Howard and sent hm the pics also and he said that the shocks will compress fully way before the swing arm hits and there should no problem. :-)
Let us do the math:
#3~#3: 329 +5mm/- 5 mm = low of 12 ž?~13 9/64 Stroke:3 1/32"/77mm
329 mm / 12.952"
5 - adjustablity
--------------------------
324 mm = / 12.75 (12 3/4")
4 - Remove the nut and screw in the shaft to maximum (aprox)
--------------------------
320 mm / 12.598" = As low as it can go at top of stroke
77 mm - (full stroke)
--------------------------
243 mm / 9.566 (a little more than 9 1/2") =
As you can see that the shock would need a whole another inch to let
the tire or swing arm hit. This is impossible to do.
Let us do the math:
#3~#3: 329 +5mm/- 5 mm = low of 12 ž?~13 9/64 Stroke:3 1/32"/77mm
329 mm / 12.952"
5 - adjustablity
--------------------------
324 mm = / 12.75 (12 3/4")
4 - Remove the nut and screw in the shaft to maximum (aprox)
--------------------------
320 mm / 12.598" = As low as it can go at top of stroke
77 mm - (full stroke)
--------------------------
243 mm / 9.566 (a little more than 9 1/2") =
As you can see that the shock would need a whole another inch to let
the tire or swing arm hit. This is impossible to do.
Last edited by SGLarry; Feb 28, 2010 at 07:56 AM.
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