OP
UTC

Enthusiast
2007 GTS 250 ie
Joined: UTC
Posts: 55
Location: Los Angeles, CA
 
Enthusiast
2007 GTS 250 ie
Joined: UTC
Posts: 55
Location: Los Angeles, CA
UTC quote
Hi there,

Has anyone ever installed this Bitubo set?

https://www.sip-scootershop.com/en/product/shock-absorber-bitubo-wmi-rear_SC180WMI01?cr=e993ab67-6807-4109-bbed-f6374ebf9f9b&gclid=Cj0KCQjwg_iTBhDrARIsAD3Ib5gHWGK0PWgtpYZkBIqTk-DRZvrEKkxqA-tBSoULMgG6EDJOOPbIqfoaAjGJEALw_wcB

Since SIP won't be restocking their rear shocks for quite some time I'm debating with trying these, the malossi rs24's, or the Zelioni shinier versions of the SIP shock. Im definitely a more spirited rider and would be welcome to sacrifice some margin of comfort for performance gain. The stock rears just never feel planted when "cornering" or having fun on local twisty roads.

I'm pretty happy with my current SIP front shock but really don't want to wait for their inventory lead time. My stocks GTS shocks are shot to hell having 25k miles on them.

I like the concept of rear shocks with a reservoir. I don't understand why it's only the left rear with a reservoir, but I'm guessing it has to do with the belt cover and all it's bits.

Any insights would be greatly appreciated.

Thank you,

HermosaBeachGuy
@steelbytes avatar
UTC

Veni, Vidi, Posti
2019 GTS300 Supertech E3 60,000km
Joined: UTC
Posts: 5550
Location: Batmania aka Melbourne, Australia
 
Veni, Vidi, Posti
@steelbytes avatar
2019 GTS300 Supertech E3 60,000km
Joined: UTC
Posts: 5550
Location: Batmania aka Melbourne, Australia
UTC quote
HermosaBeachGuy wrote:
I like the concept of rear shocks with a reservoir. I don't understand why it's only the left rear with a reservoir, but I'm guessing it has to do with the belt cover and all it's bits.
intrigues me also.

Plus I can't find them on bitubo's website? see https://www.bitubo.com/Bitubo/cms/ENG/category-cms/34-scooter.html and even their news article for the HPE doesn't mention them, only the GEV and WMB? https://www.bitubo.com/Bitubo/cms/ENG/content/324-new-applications-for-vespa-gts-300.html

yet here's a pic from the manual showing them installed on an HPE with reservoir cylinder on the left https://brocksperformance.com/content/Bitubo/Instructions/SC180WMI01V1_English.pdf
Forum member supplied image with no explanatory text
OP
UTC

Enthusiast
2007 GTS 250 ie
Joined: UTC
Posts: 55
Location: Los Angeles, CA
 
Enthusiast
2007 GTS 250 ie
Joined: UTC
Posts: 55
Location: Los Angeles, CA
UTC quote
Here is the link to these shocks on the Bitubo site:

http://bitubosrl.zucchetti.com/Bitubo/catalog/ENG/articolo/9-prodotti-finiti/zuumngdhxb-coppia-reg-precarico-molla-twin-adjspring-preloa.html

Would love to know anything more on these.

-HermosaBeachGuy
@steelbytes avatar
UTC

Veni, Vidi, Posti
2019 GTS300 Supertech E3 60,000km
Joined: UTC
Posts: 5550
Location: Batmania aka Melbourne, Australia
 
Veni, Vidi, Posti
@steelbytes avatar
2019 GTS300 Supertech E3 60,000km
Joined: UTC
Posts: 5550
Location: Batmania aka Melbourne, Australia
UTC quote
ok, found it on the main site. it wasn't listed on the listing page of all scooter shocks or on their 'news article' about shocks for the hpe.

https://www.bitubo.com/Bitubo/catalog/ENG/articolo/9-prodotti-finiti/zuumngdhxb-coppia-reg-precarico-molla-twin-adjspring-preloa.html
⬆️    About 2 months elapsed    ⬇️
OP
UTC

Enthusiast
2007 GTS 250 ie
Joined: UTC
Posts: 55
Location: Los Angeles, CA
 
Enthusiast
2007 GTS 250 ie
Joined: UTC
Posts: 55
Location: Los Angeles, CA
UTC quote
About a month ago I decided to give this Bitubo WMI rear suspension set a try.

Install was about as easy as installing a rear suspension set gets. No issues or complications. I did decide to go with the Claus Studios polyurethane bushings over the Piaggio rubber bushings.

At idle you can feel the machine be a little more buzzy, but not so significant that I would replace them with OEM rubber bushings. For now I am content with the polyurethane bushings.

With respect to the performance of the suspensions system, so far I am quite happy with it out of the box. I have not had time to adjusted this system along with the front shock for sag, spring pre-load, dampening, and compression relative to my weight quite yet. I have a newborn and my wrenching time is only so much these days. Eventually I will do so. In the front I have upgraded the suspension to Sip's offering and upgraded the brakes to Brembo along with a Zelioni brake rotor.

I can say the ride is significantly more stable/planted in the rear at high speed, and it is a much much smoother ride. The suspension system eats all the roads imperfections quite nicely. My wife was very happy about this upgrade. I imagine my dog is too.

I would say the overall feeling is sporting, and still allows for plenty of road feel despite the smoothness of the suspension. I can only compare this rear suspension to my very tired, 25K mile, stock Piaggio suspension that came off of my GTS 250. This rear suspension set has all the endless possibilities one would like for adjusting pre-load; so I imagine it can be made to feel racier, though I think one can find a rear-set more desirable if that is what one is really looking for.

At some point I would like to replace the silent block with either the stock one or the Malossi polyurethane one, though I think I will opt for stock Piaggio. I have read that the polyurethane silent block can be a bit too stiff. In addition I want to replace the engine mounts as well so I can feel as if I have really addressed all the supporting structures to the shocks themselves.

Some photos below of the installed setup.


Cheers,

HermosaBeachGuy
View from Engine bay of Claus Polyurethane Bushing and Bitubo WMI Shocks
View from Engine bay of Claus Polyurethane Bushing and Bitubo WMI Shocks
View of Gas Reservoir on Bitubo WMI Suspension (That rear brake is about to be replaced with a Brembo rear caliper along with a matching Zelioni Brake Rotor. I cant stand looking at the corroded stock caliper any longer.)
View of Gas Reservoir on Bitubo WMI Suspension (That rear brake is about to be replaced with a Brembo rear caliper along with a matching Zelioni Brake Rotor. I cant stand looking at the corroded stock caliper any longer.)
⚠️ Last edited by HermosaBeachGuy on UTC; edited 1 time
@steelbytes avatar
UTC

Veni, Vidi, Posti
2019 GTS300 Supertech E3 60,000km
Joined: UTC
Posts: 5550
Location: Batmania aka Melbourne, Australia
 
Veni, Vidi, Posti
@steelbytes avatar
2019 GTS300 Supertech E3 60,000km
Joined: UTC
Posts: 5550
Location: Batmania aka Melbourne, Australia
UTC quote
HermosaBeachGuy wrote:
My wife was very happy about this upgrade. I imagine my dog is too.
Any chance of a pic of the dog enjoying the upgrade?


PS, pretty sure those shocks don't have compression or dampening adjustments. only preload (sag).
@mayorofnow avatar
UTC

Molto Verboso
2020 GTS 300 HPE
Joined: UTC
Posts: 1346
Location: 🤷‍♂️
 
Molto Verboso
@mayorofnow avatar
2020 GTS 300 HPE
Joined: UTC
Posts: 1346
Location: 🤷‍♂️
UTC quote
Thanks for the info!

I'm due for a suspension replacement. The biggest hesitation I have to an aftermarket upgrade is the fear that "sporty" = "less comfortable." San Francisco's transportation agency isn't well known for satisfying anyone, and people on my commute are certainly included. The roads in Soma are about as smooth as a pumice stone.

Nice to know there's at least one option that might be more plush than stock when chattering over the series of cracks and potholes they call a road.
OP
UTC

Enthusiast
2007 GTS 250 ie
Joined: UTC
Posts: 55
Location: Los Angeles, CA
 
Enthusiast
2007 GTS 250 ie
Joined: UTC
Posts: 55
Location: Los Angeles, CA
UTC quote
SteelBytes

Good catch, yes only pre-load on the rear suspension.

I should have clarified all the other bits for the adjustment relative to the front and rears shocks.

mayorofnow
This is certainly more plush and surefooted than the stock rear suspension, it will handle all the shit roads CA has to offer with ease. In SoCal the road conditions are embarrassingly poor.

Pic of Loulou, my doggo, pre-ride:
Loulou ready to roll
Loulou ready to roll
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