Hi all I have a new to me sidecar rig. Its a BMW R1150GSA 2001 with a installed DMC sidecar shock trim motor.The existing front shock is a Yacugar/ Hyperpro Emulsion with Spring 46/46-070-215. My issue is the front suspension is way overloaded (sag ) with almost no travel. I'm trying to find some on in the group that has a similar bike and sidecar rig that has found the correct ( Approximate )spring that works for them?? I have look at some of the calculators on line and the just confuse me more. I have checked the load at the front wheel its 380 lbs with me on the bike on the ground and the wife standing there shaking her head asking what is wrong with the bike!!! just fix it!! Thanks for your help Steve
pretty sure @Drone has this combination, maybe a couple of other guys as well.
I've got an R1100 GS with a Progressive Suspension front shock that has a 300/400 lbs-in spring. With a static weight of 285 lbs on the front end and 170 lbs of rider it is at 28% rider sag. Preload collar is about half way up the threaded body.
Edit to add* According to the Progressive Suspension Website they use the same 435 series shock for the R1100 GS and R1150 GS. https://www.progressivesuspension.com/product/1421/435-series-shock-bmw . That wrote, I like Drew's recommendation to contact the mfg.
Not sure if this is helpful, but the bikes are somewhat similar, so hopefully it will get you in the ball park, if someone with the same rig as yours doesn't reply.
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Side note: Congratulations on the new rig. Looks pretty epic, with some very well thought of upgrades. 🙂
Hold my keyboard and watch this! 🙃
This sounds like a problem for EPM. They deal Hyperpro and know sidecars. They can size the right spring for your setup. You may need to find the weight at the other wheels.
I just bought a front and rear Hyperpro from them with springs sized for my rig and my weights. Looking at the build sheet the spring is listed as a 1624
which doesn't seem to correlate to the numbers you listed but we have different bikes anyway. I have a 2011 R1200GSA.
Hyperpro shocks do need to be rebuilt periodically. If you've ever seen liquid/oil in that area, you may need a rebuild instead of a new spring. Since this rig is new to you it may have leaked out before you got it.
Again, I would talk to EPM. Let them know the current spring size and they can guide you on best next steps.
And congrats on the new rig. Looks pretty sharp in silver.
Thanks all for your inputs so far. I rebuilt the rear shock and in the progress of rebuilding the front shock. Fun finding the Dust and Oil seals. Hopefully the correct seals will arrive soon. The rig has been fun so far added new seats, amber lights and wood dash to the car. Just this spring issue is left. Steve Santa Barbara Ca.
Hi Steve,
I have a very similar bike, down to the color, however my rig is a 2004. My numbers are incorrect and have the same issue on my rig, Unfortunately I am unable to afford suspension currently. Call Ted Porter at Ted Porter's Beemer Shop (831) 438-1100.
Ted is a west coast expert in suspension setup and does have sidecar knowledge. I would interested in your final setup.
Dave
I'm back. Just looking at the Racetech web site at the spring selection list. My spring is 46/46 -070-215 I think the 46mm is the ID second 46 is the travel and 215 is the spring length the 070 is the 070 1s the 7KG/MM = 391 lbs so if that's correct and around 400 lbs is needed, I'm close. Can it be the shock was low on oil ?? and low on shock charge of Nitrogen can that affect the front that much?? Comments please?? Thanks Steve
Quote from Steve Jensen on December 24, 2023, 5:49 pmI'm back. Just looking at the Racetech web site at the spring selection list. My spring is 46/46 -070-215 I think the 46mm is the ID second 46 is the travel and 215 is the spring length the 070 is the 070 1s the 7KG/MM = 391 lbs so if that's correct and around 400 lbs is needed, I'm close. Can it be the shock was low on oil ?? and low on shock charge of Nitrogen can that affect the front that much?? Comments please?? Thanks Steve
My experience with suspension is that the spring supports the load, oil & valving controls the speed at which the shock travels through its stroke. That wrote, if the piston in the shock is stuck it can create a situation where the spring can't extend. How much preload is dialed in with the spring? If you look at the threaded portion of the shock body how far up that part of the shock body is are the threaded collars wound?
Hold my keyboard and watch this! 🙃
Yacugar shocks for BMW GS bikes are definitely sold by Ted Porter at beemershop.com, and also of course by Klaus Huenecke at epmperformance.com. Rather than dick around with a bunch of guys who do not have hands on (or eyes on) your shock, my suggestion would be to go to one of these two guys for advice. I realize you like to do your own work but there is a point at which it makes sense to increase your knowledge base by sending the shock out for service by an expert. Both of those guys qualify. Don't think of it as an expense. Think of it as tuition. Don't bother with e-mail. Start with a call to their 800 number.
It also wouldn't hurt to mention to those guys that you're running a Stroker front wheel.
And . . . Merry Christmas!
Thanks for the inputs from you. Yes I'm a bit of a do it myself person, that the fun for me and I learn a bunch. Steve
