Sumo Springs bumpstops for Chev 3500 front

[mkguitar]

I bought the SSF-204-47 for my Van


2006 Pleasure Way Lexor on a 2005 Chev Express 3500


First impressions are good, I was looking to reduce side to side motion, sway on turns and better manage the weight shift
I put Sumos on the rear a while ago.

The online selector doesn't list for earlier than 2007 Chev express and it took some communication with Mark Jutson thanks to themexicandoctor to get some measurements.

the only tools needed are 2 or 3 large screwdrivers and a large set of channel locks ( 16") or pliers, with jack and stands

the first side took about 40 minutes to figure out tools & method, the 2nd side took 15 minutes


raise front of van, place jackstands. parking brake and chock rears

for driver side turn steering wheel all the way right, you can lean past tire to get to bumpstop

push medium/large screwdriver up past bumpstop into mounting cup at the inside, then a large screwdriver beside it and lever the bumpstop out.
mine was # 15750835 measuring 2.4" diameter at the mounting ridge.

The cup has 4 tangs which are used to hold the bumpstop in place.
I used the channel locks to push back the 2 tangs at the rear and at outside of the cup


the Sumo is 2.51" diameter at the ridge, so larger but smushable


I was able to get the new bumpstop in place about 280º, with 80º to the outside not quite seated

with the van supported on the stands.

With my jack I lifted the lower A arm to get pressure on the bumpstop and then using dull screwdrivers (or similar) pushed and worked the mounting ridge into the cup.
Once in, use a screwdriver to push the 2 tangs back into position- when your screwdriver has made a 3/16" gap seems right.


job done

now repeat other side

when van is down on the ground eyeball that the bumpstops are fully seated before test drive

on return from test drive, I checked the tangs again

mike

[themexicandoctor]

Thank you. Good info.

[mkguitar]

BTW https://www.superspringsinternational.com/


is selling 25% off in December


when searching be careful as the first few google results are "sponsored results" from 3rd party vendors which may be priced higher


mike

[bwatters60]

MK,

Thanks for posting your information. I had replaced my bump stops on my '04 Suburban last year, and it took the sway out in cornering. So I knew for some time I had to check my bump stops on my 08 Roadtrek 210 ('07 chassis). Before getting around to checking them, I saw your post and knew I had to order the sumosprings. Unfortunately I was too late to get the December sale price, but it was still worth it. The springs were really easy to install (I used a channel lock to twist and pop the old ones out, and then used compression and a screwdriver to install the springs), and it has made a dramatic improvement in the drive and ride of my Roadtrek. The sway is gone on cornering and it really hugs the road. It's a pleasure to drive! I've included some pictures that may help someone else.
Thanks again! Bruce

[bwatters60]

My pictures of my old bump stops and new sumosprings. BTW, I just did the front and have no plans to add springs in the rear.

[rowiebowie]

Nice pics!

Your OEM bump stops from your '07 chassis look better than the OEM's off my '11 chassis which were cracked and probably needed replacing years earlier. My black Sumos were installed after my 2-1/2" lift so they sit slightly above or just on the suspension. Without them, I'd have had quite a bit of travel before they contacted if I'd gone back with new OEMs.

For those considering Sumo Spring bump stops, the consensus is Black for front, Yellow for rear. I can't recall anyone reporting negative results.

[mkguitar]

My oem bumpstops ( 2005 part #15750835) looked much like his.


and at stock height, my sumos look much like his



mike

[folivier]

The Sumosprings act similar or in addition to a sway bar? Do these improve or reduce the ride smoothness?
My 2011 C210P drives well but I do get buffeting from 18 wheelers I'd like to reduce.
Or would adding air springs do a better job?
Thanks!

[booster]

Originally Posted by folivier

The Sumosprings act similar or in addition to a sway bar? Do these improve or reduce the ride smoothness?
My 2011 C210P drives well but I do get buffeting from 18 wheelers I'd like to reduce.
Or would adding air springs do a better job?
Thanks!

Anything you do to the weight support areas such as Sumos, new springs, spacers, shocks, etc are totally different from what swaybars do. Stiffening up or damping more in weight support may reduce sway a bit, but that is generally not the prime reason for them. Ride height, ride comfort, up and down motion control of the wheels to keep the tires on the road well are the prime things. Any improvements are from the increased stiffness and damping which tend to limit suspension travel


Swaybars are totally different as they support no weight of the van at all. They do absolutely nothing on a smooth road in no wind or other disturbances. The only thing the do is prevent sway of vehicle side to side by making the wheels share more equally any side to side loads. If you have a big wind gust hit the van in the side with no sway bar, the side hit will tend to go up a bit and opposite side will go down, tilting the van and trying to steer it on top of just force of the wind pushing it over. One side tire looses some traction and the other side gains some so can cause a pull also. The same wind with a sway bar on each end of the vehicle will take the extra load on the non wind side wheel and share a lot of it with the wind side, keeping the van more level and tires more equally loaded. preventing a lot of the push from the wind and then the sway back when the wind drops again. Swaybars can increase bump harshness some but only on bigbumps that hit on one side of the van. They will help prevent the van from going off straight ahead in those bumps, though.



The second thing that swaybars do is to balance the traction from from to rear by shifting available traction end to end. How they do it is complicated, but the "rules" are pretty simple. Basically the bigger the swabar is one end, the more traction it gives the the other end. This sounds backwards but is the way it works out. Adding a rear bar to a Chevy RV will transfer traction to the front and that will greatly improve the way the van reacts to inputs form the steering wheel. That improvement means smaller corrections in the steering to keep the van going straight after things like wind gusts. Vans usually come with no rear bars because they are light in the back before conversion to an RV when the get very heavy in the back, so rear traction loss is not an issue like it would be with light rear empty van.


Some users have been just fine with just adding Sumos as the Chevies are quite good to begin with and just getting the van up off the overload leafs in the rear springs with the Sumos will reduce the quite violent "pitching" you can get on bumps, or with hard wind hits, because of sitting on the rock hard overload leafs. Others like me prefer to add a bar and either Sumos or other ways of lifting to improve the steering response to make easier driving. The whole thing with tuning the steering response is very personal choice driven. Some prefer a vehicle to react a bit slowly to prevent overcorrecting all the time. Two hand firm on the wheel all the time folks tend to be that way, I think, and might find a quicker responding van like ours to be too twitchy. More light on wheel, often one handers like me, prefer the small and easy to make corrections.


IMO, do the Sumos if that is your suspension side preference and make sure to replace or confirm that the shocks are good. There are several brands the folks recommend that will improve ride and handling. Our preference is Bilsteins. Make sure you have what you find to be optimum tire pressures for you preference. Most like around 65/80 or so. Make sure it is aligned well and as near to optimum as you can get somebody to do (hard to find these days). Optimum settings are stated in many discussion on this forum.


If you still would like to reduce wind, truck, bump influences you could then put in a rear bar of at 1 3/8" diameter. Don't ever just increase the front swaybar size in the RV vans as it will make handling worse in most cases, and don't increase the front size when you add a rear bar as it negates some of the rear bar benefits.

[mkguitar]

15% off coupon code:


SUPERSTEELRV

https://www.superspringsinternationa...eid=5ff2c16afe

[mkguitar]

Foliver,


I couldn't add a sway bar due to the location of my generator- that would have been 1st choice for my pleasure way on a chev van


so I have the same black sumos replacing the front bumpstops and the rear sumos also in black


This helps with some side to side waddle, wind gusts n stuff.
I suppose it reduces any motion and spreads it over a longer time



and for the cost and the couple of hours crawling under the van a good return


Mike

[booster]

Originally Posted by mkguitar

Foliver,


I couldn't add a sway bar due to the location of my generator- that would have been 1st choice for my pleasure way on a chev van


so I have the same black sumos replacing the front bumpstops and the rear sumos also in black


This helps with some side to side waddle, wind gusts n stuff.
I suppose it reduces any motion and spreads it over a longer time



and for the cost and the couple of hours crawling under the van a good return


Mike

Did you look at the Roadmaster swaybar? They have been put on the Roadtreks with generators, I know, and they are very close to axle. That is how we wound up with our homemade custom bar which is like the ones used in circle track cars.

[folivier]

Booster thanks for the great explanation, I think I know enough now to crawl under and what to look for. Not knowing what the previous owner did puts me at a disadvantage until I get underneath.

[mkguitar]

Originally Posted by booster

Did you look at the Roadmaster swaybar? They have been put on the Roadtreks with generators, I know, and they are very close to axle. That is how we wound up with our homemade custom bar which is like the ones used in circle track cars.

with van on jack stands, I used my jack to raise and lower the differential through the range of travel. I have 2.75" clearance between the pumpkin and genny. it's tight.


I keep thinking about loosing the genny which would easily allow a sway bar.


we have never once used the genny while camping


- anyway, the Sumos front and rear make a real positive change on speedbumps, curves and turns. Did a bit of a drive the other day and was happy with the results.



Mike

[booster]

Originally Posted by mkguitar

with van on jack stands, I used my jack to raise and lower the differential through the range of travel. I have 2.75" clearance between the pumpkin and genny. it's tight.


I keep thinking about loosing the genny which would easily allow a sway bar.


we have never once used the genny while camping


- anyway, the Sumos front and rear make a real positive change on speedbumps, curves and turns. Did a bit of a drive the other day and was happy with the results.



Mike

The 2.5 inch clearance if probably what we had with stock axle and generator in place. I think we have even less now with the 10.5" rear axle.


The bar I used doesn't use the normal bend in the middle back around the pumpkin cover, as it goes straight across under the furthest back part of the cover and doesn't really sit much to the rear of the cover itself, if at all and is not lower than the bottom of cover. The arms go under the rear axle to the frame in front of the axle like a normal bar would do. It works very well and is even setup to be able to change out the bar easily if I want to change the rate of it, which I have done once when I went from 1.375" to 1.500" diameter. The arms hook on with splines and a bolt so just pop them off and change the bar.


Sumos will flatten it out some in corners but is not really sway it they are controlling. The are just increasing the spring rate of the axle so the sway is proportionally less but still there. The downside can be roughness of ride to doing it that way, but if it is tolerable that isn't an issue, and on a Chevy if you get high enough up off the overload spring you can reduce the banging you get from hitting the rock hard overload leaf on bumps and dips, which is a big deal, and loud noises it generates when hit.


Our final solution to it all was to actually reduce the rear spring rate by using the airbags, which are lower rate, to carry about half the load or a bit less on the rear. Of course this increases travel. I then removed the overload leafs to get rid of the slapping on it. To prevent overtravel with the overload gone, I used the newer style bags that have a bump stop internally to do a soft landing on big bumps with no overtravel or harshness. The results have been very, very good with a much smoother and much quieter ride in the rear. To bring the roll stiffness (antisway) back to where it was with stiffer springing and get the understeer tendencies the same as before, I just increased the sway bar size. We wound up with best of all worlds.

[mkguitar]

Thanks, appreciate this.


I just had a another look at available local roadmaster dealers (due to clearance, I'd farm this out to someone who does this all day every day). I may talk to someone



I have a 6000 mile trip in May planned and that'll give me plenty of seat time to appreciate- or not- this set up.


I've never noticed or experienced much of the helper springs, never appeared to bottom or top out on the suspension-
even on washboard the tires stay in good contact with the road


thanks, Mike

[booster]

Originally Posted by mkguitar

Thanks, appreciate this.


I just had a another look at available local roadmaster dealers (due to clearance, I'd farm this out to someone who does this all day every day). I may talk to someone



I have a 6000 mile trip in May planned and that'll give me plenty of seat time to appreciate- or not- this set up.


I've never noticed or experienced much of the helper springs, never appeared to bottom or top out on the suspension-
even on washboard the tires stay in good contact with the road


thanks, Mike

Have you taken a look at the rear springs on your van? You can see toward the front and rear of them that the bottom leaf, which is the helper is usually touching or maybe 1/8" from touching the other leafs above it. On bumps is hits and particularly dips, it can hit and give harshness and noise but only if there is a gap to start with. If no gap just very stiff in the rear. A lift will get you up off the overload further. A 2" lift typically will give 1/4" or a bit more. Depending on the spring rate of the lift, bags are quiet low in rate, Sumos higher in rate, that gap may or may not close enough to slap on big bumps or dips. The horrible ski jump like transitions to bridges in some places were the worst for us.



If you are lucky, you may get a balance of gap vs rate with Sumos, I know with bags it still would hit depending on the size of the bumps or dips. It also will be interesting for you to see if you get any pitching from single wheel dips with the higher rate. Sometimes you will get that when increasing rate without adding anti sway at the same time. When our van was almost sitting on the overloads the pitching was very obvious to me, but now is essentially gone.

[mkguitar]

I find my ride to be comfortably "floaty", never harsh. as I said no topping or bottoming in the suspension.


at stock height the sumos do contact the axle and are compressed maybe 3/8"


the waddling/swaying is reduced


with the addition in the front to the chev, the sumo bumpstops are compressed somewhere between 5/8 ~ 3/4 " ( eyeball guestimation).
the front end definitely feels more sure/stable
- this is more a consequence of getting the old worn stock bumpstops out- more than adding sumos.



I drove trucks & coaches for years, my driving tends to be soft on gas and brake and gradual turns- to keep from tossing cargo or people around.



mike

[booster]

Originally Posted by mkguitar

I find my ride to be comfortably "floaty", never harsh. as I said no topping or bottoming in the suspension.


at stock height the sumos do contact the axle and are compressed maybe 3/8"


the waddling/swaying is reduced


with the addition in the front to the chev, the sumo bumpstops are compressed somewhere between 5/8 ~ 3/4 " ( eyeball guestimation).
the front end definitely feels more sure/stable
- this is more a consequence of getting the old worn stock bumpstops out- more than adding sumos.



I drove trucks & coaches for years, my driving tends to be soft on gas and brake and gradual turns- to keep from tossing cargo or people around.



mike

It would still be interesting to see where the springs are sitting in relation to the overload though, as that has been an issue for nearly every Chevy class B in the rear except the 2500 van base versions.

[KurtFranz]

Mike-

Getting ready to take the plunge.... I have an 02C190 - I am assuming that the same items that worked on your 05 will suffice for me as well.

If anyone has bad news for me based on actual experience please let me know.

Thanks!

Originally Posted by mkguitar

I bought the SSF-204-47 for my Van


2006 Pleasure Way Lexor on a 2005 Chev Express 3500


First impressions are good, I was looking to reduce side to side motion, sway on turns and better manage the weight shift
I put Sumos on the rear a while ago.

The online selector doesn't list for earlier than 2007 Chev express and it took some communication with Mark Jutson thanks to themexicandoctor to get some measurements.

the only tools needed are 2 or 3 large screwdrivers and a large set of channel locks ( 16") or pliers, with jack and stands

the first side took about 40 minutes to figure out tools & method, the 2nd side took 15 minutes


raise front of van, place jackstands. parking brake and chock rears

for driver side turn steering wheel all the way right, you can lean past tire to get to bumpstop

push medium/large screwdriver up past bumpstop into mounting cup at the inside, then a large screwdriver beside it and lever the bumpstop out.
mine was # 15750835 measuring 2.4" diameter at the mounting ridge.

The cup has 4 tangs which are used to hold the bumpstop in place.
I used the channel locks to push back the 2 tangs at the rear and at outside of the cup


the Sumo is 2.51" diameter at the ridge, so larger but smushable


I was able to get the new bumpstop in place about 280º, with 80º to the outside not quite seated

with the van supported on the stands.

With my jack I lifted the lower A arm to get pressure on the bumpstop and then using dull screwdrivers (or similar) pushed and worked the mounting ridge into the cup.
Once in, use a screwdriver to push the 2 tangs back into position- when your screwdriver has made a 3/16" gap seems right.


job done

now repeat other side

when van is down on the ground eyeball that the bumpstops are fully seated before test drive

on return from test drive, I checked the tangs again

mike