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Old 06-28-2017, 11:38 AM   #21
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Originally Posted by penguin View Post
As Jamie said they do a lot more than just address sag.
You're correct, they do. In fairness to the point made by blw2 (that they are primarily a helper spring), the description given by JamieGeek is consistent with stiffer springs which is a common configuration for helper springs.

Simply replacing springs with heavier/stiffer springs (or installing multiple springs in combination to do the same, as in Sumos) would also reduce mushy ride, reduce lean on turns, and would also lift front end some if replaced with comparable-length OEM coils.

Quote:
Originally Posted by JamieGeek View Post
I found that it tightened up the front for me. The Axis no longer seems as mushy in the front and doesn't lean near as much in turns as it used to.

That Sumos often replace OEM bump stops for convinience and ease of installation seems to muddy their role somewhat. As shown in posted pictures they are essentially a helper spring to make suspension stiffer. It's not that different than small air bags that also replace bump stops; except that they are not adjustable. They may also provide a small amount of damping which steel coil springs or air springs don't to any significant amount.
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Old 06-28-2017, 12:05 PM   #22
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Brand: Thor Motor Coach
Model: Windsport 31S
State: Florida
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THOR #4443
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Originally Posted by schreinertms View Post
What is the difference in the color of the Sumo springs? Some model numbers show up in black or blue. If that a significance? And then there are yellow ones?
The blue ones are the lighter weight 106-40's (500lbs). The black ones are 106-47's (1000lbs). I think yellow is for the rear. Per sumo literature the blue ones are for a van (lighter weight) and the black for a box truck. I would say the blacks are better suited for the Axis/Vegas as they are very heavy.
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Old 06-28-2017, 01:04 PM   #23
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Model: 37GT
State: Florida
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Originally Posted by greenfield3 View Post
I am not inclined to install them on my 37KT, What is a reasonable price to have them installed? My dealer is quoteing $1k.
For the heavier F53 chassis (front and rear) I paid around $1,130 on line to get them. I was thinking of installing them. After reading instructions for my coach and finding out how many holes had to be drilled plus needing a jack big enough to raise the rear axle, I decided to have a shop install. The RV shop that installed them had never done a set, they had only done air bags. They charged me just under $800.

Total = Just under $1,950
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Old 06-28-2017, 01:16 PM   #24
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Originally Posted by vkb View Post
Ron is happy with our Sumos Front and Rear. We will give then another test next week...heading to Colorado. Winds of western KS & east Colo will not be such a challenge with them.
We now have just over 1,600 miles on the Sumos and my observations are:
* at first the ride seemed a little harsh but they now feel "broken" in.
* on calm days it is like driving your car down the interstate.
* in 20mph plus cross winds you feel much more stable and in control.
* no noticeable lean when making slow tight turns.

Even though we generally only do around 300 to 350 miles a day, I am confident by the way the coach handles now that I could easily do a 600 mile day if needed.
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Old 06-30-2017, 10:27 PM   #25
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I posted pictures of height measurements before and after Sumo install ... measured again after an hour or so of driving around town and the result shows it settled back to within 1/8" of the before measurement. This is good news in a way because there should be no need for another alignment Initial in town observations are that the Sumo's did eliminate the harshness of bump stop impacts. Hitting the highway and into the wind now ...
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Old 06-30-2017, 10:38 PM   #26
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I installed the front 106-40 sumos that I purchased on Ebay for $100, we have since completed a 6500 mile trip in our Axis and I found that they significantly reduced the jolting in the front end when hitting bumps.
The front Sumos, an alignment, and front and rear heavy duty anti-sway bars have our Axis handling very comfortably.
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Old 07-03-2017, 02:09 AM   #27
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Well ... after a couple days of driving on many familiar surfaces with the HD/1000lb Sumo bump stops mounted. I noticed no negative behaviors! Most noted improvement is smoother handling of surface transitions and less rolly polly on patched, uneven, frost heaved roads. Fairly easy comparison because our rig with only a trackbar added, over 2yrs ago now, has had no other chassis mods.

We departed on the freeway into erratic headwinds much like most of our departures where we take the freeway. I could feel and hear the wind hitting the coach from an ever changing direction. My impression was that of slightly less effort needed to stay in lane at around 75mph with wind and vehicles passing at 80+ ... though effort/attention was still needed ... partly because 75 is a bit too fast in those conditions. Quite noticeably less effort and reduced floaty feel on the rough two lane road surfaces we traveled. On the way back we had of course the typical wind conditions where a very comfortable 71mph was "guess/estimate" netting a mph or two more in a relaxed cruising speed (very subjective to conditions e.g. not positive yet, though no complaint). I've driven this route many times in similar, higher and lower wind conditions so I do have decades of driving various RVs on the same roads. But most importantly have continuous input from a very sensitive passenger

My takeaway is; don't be afraid of the HD (1000lb) bump stops if you are front heavy on the E chassis! Pretty cheap and simple to install. Eliminating the bump stop impact is a good experience, for sure on rougher surfaces and I noticed no increased harshness on the smoother road surfaces.

Here's a picture of last night's sunset from our camp chairs ...
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Old 07-04-2017, 04:01 PM   #28
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When I took the measurement where I previously mentioned that it settled down to near original height, it was based on measuring the nearest side (R). Didn't think much of it and expected things to settle down from the fresh off the jacks measurement (middle in the pic clips) as I didn't figure there would be much lift. Just assumed the other side would be the same e.g. didn't give it much thought.

Anyway, I got to thinking about the considerably lower left side so I measured and it looks like the Sumo's are pushing up to the tune of about 1/4". That side had noticeably less space between the bump stop and therefor higher compression so Sumo's progressive spring rate must be working full time to net 1/4" lift at rest (carried weight). I even put the slide out to make sure that measurement matched whatever position it was in when I took the first picture before the Sumo install.
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