R Racing-Modified Internal-Reservoir Ohlins

Discussion in 'Trials' started by motobene, Jun 7, 2017.

  1. motobene

    motobene Motoing for 46 years

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    Starting a stand-alone thread on this. There is a related thread with similar name here:

    http://advrider.com/index.php?threads/sherco-ohlins-prototype-shock.1207385/

    ...but the subject matter is different. Same brand of shock for Sherco application, but this thread regards increasing the travel and performance of the OE Ohlins with internal gas reservoir that comes on many trials bikes.

    Randy Lewis of R Racing has a modified non-remote-reservoir OEM Ohlins shock on its way for testing and evaluation.

    The Ohlins shock for Sherco Factory models has been around many years. It's a solid, reliable shock that tends to be a bit harsh during break-in, then works fairly well.

    The modification push resulted from discussions we have had. While Randy's R Racing longer travel remote reservoir shock, I was hoping for a tweaked and improved version of the internal-reservoir shock, based on some of the same principles employed in the long-travel remote reservoir shock, which are:

    - Added negative travel
    - Added positive travel
    - Shim-stack tweaks (re valving)
    - Softer spring

    When I get the shock, I will take pix and do direct comparison rides to report on here.

    If the modded shock proves out, one could improve on the Factory Ohlins without buying a whole new shock. While it may not work quite as well as the long travel R Racing shock with remote reservoir and compression adjuster, the modified shock could result in a noticeable improvement over the standard-issue Ohlins without having to buy a whole new shock.
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  2. motobene

    motobene Motoing for 46 years

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    Results are in!

    The addition of negative travel (the swing arm can extend down a bit over stock) and softer spring extension force, the ground-following and traction is VERY noticeably superior with the modified shock! The overall feel is plush and deep. The stock Ohlins feels abrupt and 'bony' in comparison. Landing hard off a drop off is VERY much improved. This shock should bottom harsher with a softer spring, right? The opposite is true. The combination of the added travel, softer spring, and slight re valving make it difficult to tell when the shock bottoms. It's odd how well the modified shock can soak up major hits.

    Performance is superior, but what about timing? Randy made a big point to emphasize that I'd have to reprogram my timing with the modified shock. If I did go through reprogramming, the period was so short I have no memory of it. The transition was completely natural for me. I found myself better, not worse, at rear-end hops, for example, as landing from them has less tendency to bounce me out of balance. Landing the rear with the brake on feels very plush.


    Rear axle travel increased from ~5-1/2" (140mm) stock to over 7" (178mm) modified.

    On the latest Sherco-Scorpa (I'm not sure about the airbox-in-front models), the shock only fits well body-end-down (rod end up) because the support strut in front of the shock is very close to the shock and will hit the spring and preload nuts when the shock is turned body side up.

    The modification is not easy given the nitrogen gas separator piston has to be in a very specific position during reassembly, so this mod is best done by an experienced person.

    Attached Files:

    #2
  3. motobene

    motobene Motoing for 46 years

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    Gosh I thought this post would generate more interest, but I think perhaps the technical language may sound like Mars Attacks! dialogue to the majority? Ack ack ack ack!

    Several rides into the modified shock I continue to be very impressed! Much more plush and yummy!

    Randy said he wants me to keep the shock for a few months to fiddle with the settings and compete on the bike. Very happy to!

    I'm so impressed with increasing the travel that I will modify two Sachs ZF shocks I have in a similar way. The Sachs ZF takes Ohlins 12mm ID shims and when the piston is flipped over the right way and the damping is fixed, the longstanding standard GasGas shock works better than a stock Ohlins shock, in my humble opinion. Now it can work even better.

    I wish I could test the longer GasGas shocks on my Sherco, but I can't, and I no longer own a GasGas. But KrAzYOSUcowboy does, and one of the two Sachs shocks is his. I'll ask him if he wishes his rebuilt in the longer-travel direction.

    This investigation is getting very interesting... to me, anyway:jive
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  4. Zuendapp

    Zuendapp Been here awhile

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    Being from a Offroad and vintage motocross back ground, I am amazed that not more trials riders have there suspension tailored to better suite them. You can not convince me that a 250 Lbs. rider doesn’t need stiffer springs?Or a lighter fly weight rider need softer setup.

    I have read in the past that it is technique and skill, Of course if you have been riding trials for 20 plus years you have the skill and technique. Unfortunately many newer people to trials do not or will not ever have the 20 plus years experience. This is when the suspension setup makes for a more enjoyable and safer ride.

    The other explanation is cost, don’t need the Reiger or Ohlins shock. Maybe so, playing tiddlywinks is cheaper than trials. I would rather ride trials motorcycles, even though tiddlywinks is challenging.

    I have been intrigued by “R” Racings modified longer travel shocks. I can’t wait to read more on the “R” Racing Ohlins Sherco shock evaluation.
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  5. DRZBRI

    DRZBRI Bumblebeetuna!

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    you can borrow my gas gas if you want. It needs a new base gasket anyway. lol
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  6. motobene

    motobene Motoing for 46 years

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    I re valved and added some travel to a Sachs ZF shock today. It's being delivered tomorrow. Hope the customer likes the changes!

    The Ohlins is far easier to disassemble and add travel to. The Sacks has no spacers that can be removed, and the bump cushion is shorter on the Sachs, so not much of it can be pared back.

    It was a little here and there with a the Sachs, via machining three parts and modifying the bump cushion. I was able to eke out a whole 10mm more shaft travel:raindance
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  7. motobene

    motobene Motoing for 46 years

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    Trials suspension is pretty good, and works for a wide range of riders. Custom work can help, but we don't have a culture that promotes spending money on suspension. That is both good and bad.
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  8. Vintage pro

    Vintage pro Been here awhile

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    Chris , make sure you test the std. 65nm spring just to my point of spring being overly stiff. On the TRS shock I built , I ended up with a 55nm spring , almost identical valving with almost no clicks in on the compression adjuster.
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  9. jonnyc21

    jonnyc21 Trials Ninja

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    I am sure on the edge of my chair for the next installment... :thumb
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  10. motomofo

    motomofo Been here awhile

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    I agree with you, but to also support Zuendapp's point of view... how many people who ride trials pay attention to how much sag they have? Very, very few. And it does make a difference. This is the first thing that anyone in any other motorcycle discipline focuses on during setup, yet trials riders typically ignore it.
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  11. jonnyc21

    jonnyc21 Trials Ninja

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    Its interesting that we don't really have a culture that promotes spending on things like suspension and similar adjustments as often as other motorcycle sports. Yet if you look at some of the top riders like Bou or Adam you see they have custom setups for more than just suspension. Even Pat has a modified setup, though not nearly as much so as the world level riders, with stiffer settings in the rear for the big hits and a stiffer clutch etc.

    I am not saying we should be setting our bikes up like Bou, Adam, or Pat... however if we are willing to dive in just a little more than we typically do as a trials community I would think it would help in the end. And even better would be share what you fine like motobene so we all get to see what works and doesn't we all get better togeather. And it might also attract a few riders from other disciplines who see trials as a black box of it will make you better but how?

    I will stop my rambling and let the thread get back to what its intended for. :freaky
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  12. Bronco638

    Bronco638 Nobody Home

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    I would love to tinker with my suspension because I'm pretty sure it's not set-up correctly, for me. However, I can read about stuff all day long but until I touch it with my fingers, it doesn't really sink in. I truly appreciate Chris' efforts and the fact that he takes time to post but, in this case, I'm still in the "suspension changes = black magic" mind set. I wish it lived closer to SW Oklahoma.....
    #12
  13. lineaway

    lineaway Long timer

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    Funny a video was just added to the link section at the top of the start up page. It was from Ryan Young talking suspension. what a 7 times National Champion and Sherco importer and one of the best trials trainers in the country. Watch it and see. Not once did he mention a measurement for sag. Just that you need just a little bit. I have been riding trials since 1972 and this was the first year that I bought a stiffer spring for my rear suspension. Granted I still worked alot to make the sispension to work correctly. The funny thing is I have lost more than 30 lbs since I installed the spring. At this rate I will be putting the stock one back on soon.
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  14. motobene

    motobene Motoing for 46 years

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    I like the fact that we keep it simple and don't geek out too much.

    Regarding sag in the rear, a great simplification is to ignore loaded percentages entirely and simply measure how much the rear fender drops under the bike's own weight (assumes the typical 65 to 70 N/mm spring and typical shorter travel).

    If you are a lard butt, 5/8" will do. If a fly weight, 7/8" will do. Interpolate in between. If you go with a stiffer rear spring you may need less preload to get the 'butt drop' needed to retain more neutral (less hyper) steering.

    My current modified shock is and exception to the butt drop rule, having 1.4" of drop even with the softer 60 N/mm spring. The added negative and positive travel require this exception to preserve more neutral steering, the same stable steering I had on this same bike with stock Ohlins was 3/4".

    I will continue to repeat and emphasize steering characteristics as very connected to sag and bike saggital-plane bike pitch. You'll seldom hear that emphasis elsewhere.
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  15. motobene

    motobene Motoing for 46 years

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    Rode for an hour again last night.

    The simple mods are continuing to be superior and very noticeably pleasurable!

    After a few more ride hours I'll swap back to the stock Ohlins for recalibration. I am 95% sure at this point that my reaction to the stock Ohlins will be negative.

    It's hard to describe, but the ground compliance and obstacle soaking capabilities of the modified shock are very noticeably improved. The rear end has a deeper feel that lacks harsh bottoming. I've engaged in a certain perverse joy at attacking the sea of large fixed rocks the ranch has so many of. My skid plate isn't liking when I make small errors in line selection or balk when a lifting and placing of the front wheel from one big rock to another gets scary, but I am having some great :ricky
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  16. Tomnz

    Tomnz n00b

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    I wonder if this modification could be done to the trp sherco shock? I currently run one of these in my Scorpa and while it is significantly better than the standard shock it could be better
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  17. jonnyc21

    jonnyc21 Trials Ninja

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    All this talk of the R Racing modified Ohlins makes me want to try one... But I think I will have to be happy with what I have for a bit... :deal
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  18. Norman Foley

    Norman Foley Devotee of the Husqvarna

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    At least break it in first!:getiton
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  19. motobene

    motobene Motoing for 46 years

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    I love the Ohlins for it's simplicity, flexibility, and ease of maintenance. I like how Reiger shocks work but don't wish to own any more because they are purposed to not be easy to disassemble.

    The use of internal travel-spacers on the Ohlins, one of which can be removed for more negative travel, and the tall bump-stop cushion which can be shortened for more positive travel, is a flexibility that allows the Ohlins to be even better.

    It's a shame the Ohlins aren't set up our way as they would definitely be preferred by riders.

    Missing from flexibility is that Ohlins no longer stock the 60 N/mm 00281-13 spring. Though only a little less stuff than the 65 N/mm 00281-64/65 spring that comes on the shock, the softer spring enhances the performance when the shock when modified for longer travel.

    I have been searching for some other 60 N/mm (350 pounds per inch) spring but have yet to find one in something close to 46mm ID and 125mm length. I can remove OD material from the spring, but first I will try the 65 N/mm spring at zero preload.

    As for applying this modification philosophy to other shocks, it can be done. I got part-way there with a Sachs shock recently, but was held back by tge shorter Sachs bump cushion.

    I don't know about the TRP shock because I've never had one in my hands.
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  20. motomofo

    motomofo Been here awhile

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    Cannon Racecraft in OKC can make you whatever spring you want. Usually takes about two weeks. They produce MX/street springs for several aftermarket companies. I think the last custom shock spring I had made for a dirt bike was about $125... totally reasonable for a one-off spring.
    #20