StromTrooper banner

1 - 20 of 78 Posts

·
Registered
Joined
·
652 Posts
Discussion Starter #1
I think my front rim is made out of tin foil. :-(

I bent it in 3 spots back on April 24; driving down a semi-rocky forest service road. I found a retired machinist who bent it back into shape.

Then last week I was on a back road that turned out to be insanely rocky. I slowly picked my way thru, thinking "this has to end soon" and that just around the bend it'll smooth out. Nope. And somehow, 6 miles in, I noticed my front end was squishy. Stopped to look, and sure enough I had a huge dent in the rim; big enough that it couldn't hold air.
274487


I grabbed a large rock and beat on the rim a bit, but couldn't bend the rim back at all. So I turned around and rode 6 miles back on a flat front tire over this insanely rocky road.

Then I turned in my man card and called my wife. :) She brought me my 5lb sledge hammer and the handle from my old floor jack, and I pounded the crap out of the rim until it held air, then rode 20 minutes home with no issues. Looks like crap now, but at least it held air!

274492


And it's still holding air; loses maybe 1 psi per evening.

This is a cast aluminum rim, correct? ('04 DL1000) A guy at work that's studying metallurgy told me that beating on the rim has either made that spot brittle, or super hard. Or both. He's not exactly sure. :) Anybody here know? Also, could the previous work that was done fixing the other bends (heat was used) have weakened the entire rim?

I don't know why my rim is bending so easily. Maybe my new springs are too stiff? I can't set the sag on my forks because when I sit on the bike, the forks don't compress at all. (If I bounce the bike, the forks compress; they also compress when I use the front brakes.)

Anyway, I'm not exactly sure what to do now; I'll be looking for a new front rim, but am I just going to bend that one too? I don't see many (any) "bent front rim" posts here.
 
  • Like
Reactions: Aclew

·
Registered
Joined
·
652 Posts
Discussion Starter #3
I'm running a Shinko 705 on the front, and an hour before the bent rim I'd checked the pressure and it was 35 psi. I don't know exactly when the bend happened; but I don't think I was ever going faster than 20mph...most of the time I was going much, much slower, trying to dodge the big rocks.

Since my left fork seal has a tiny leak, and it was very dusty on that road, I can clearly see that the suspension never bottomed out; not even close. Which is why I'm thinking my springs may be too stiff.

I never once felt like I'd been bounced sideways or up in the air, or like I should have been launched off the bike, either this time or the last time. Yet the rim bent that bad anyway!
 
  • Like
Reactions: DesertBike

·
Registered
Joined
·
652 Posts
Discussion Starter #5
Bash aluminum once and it's work hardened. It becomes brittle. As Oldjeep suggests, you may not be using the right tool for the job.
That's what the guy at work said, but that seems like an oxymoron: it's hardened and it's brittle? My brain doesn't understand; seems like it would be one or the other? So if I hit another rock in the place where I bashed on it, is it going to hold, or is it going to shatter?

I think I'm using the right tool (other vstroms can go down the same road and not bend a rim); but I think my tool may need either it's forks tweaked, or it's rider needs to figure out how to not hit invisible rocks...
 
  • Like
Reactions: DesertBike

·
Registered
Joined
·
656 Posts
It is hardened and brittle. It won't bend quite as easy next time but it won't simply bend, it will crack badly. You could hammer that on out and sand it, paint it and use it only on the street if you are not too risk averse.

If you continue with your 500 lb dirt bike with a new rim You might want to look into lighter fork oil. let the fork move more right up to bottoming out, then go back to slightly thicker oil until it travels and absorbs bumps but doesn't quite bottom out. back in mx days the thought was that the bike should bottom out once lightly on the worst hit. then you add a little more f oil to prevent that. you want the suspension to move just shy of, or barely bottoming out.
good luck
 

·
Registered
Joined
·
448 Posts
When off-road, try reducing air pressure to 15-20 psi and let the tire help do the suspension work. This is why most off-road set ups use wire spoke rims instead of cast...the same forces on a wire spoke wheel would have left no evidence of trauma. Right tool, and all...new rim is called for this time and that is for sure gonna' leave a mark!
 

·
Registered
Joined
·
96 Posts
I'm running a Shinko 705 on the front, and an hour before the bent rim I'd checked the pressure and it was 35 psi. I don't know exactly when the bend happened; but I don't think I was ever going faster than 20mph...most of the time I was going much, much slower, trying to dodge the big rocks.

Since my left fork seal has a tiny leak, and it was very dusty on that road, I can clearly see that the suspension never bottomed out; not even close. Which is why I'm thinking my springs may be too stiff.

I never once felt like I'd been bounced sideways or up in the air, or like I should have been launched off the bike, either this time or the last time. Yet the rim bent that bad anyway!
Shinko 705 are available in both bias and Radial, if you are riding in a rocky area I suggest Bias as they have much stiffer sidewalls.
Radials are better for gas mileage and comfort so better for touring.
Tire pressure cold with radials is supposed to be 36psi front and rear solo on the Gen1 DL1k
With bias tires you run a bit lower pressure, solo I run about 30-32 psi but off road I can run 25 and still have a stiff enough sidewall for a moderate hit from a rock.
Thats theoretical as I dont air down for offroad :) or I should say I have not yet...
 

·
Registered
Joined
·
2,920 Posts
That's what the guy at work said, but that seems like an oxymoron: it's hardened and it's brittle? My brain doesn't understand; seems like it would be one or the other? So if I hit another rock in the place where I bashed on it, is it going to hold, or is it going to shatter?

I think I'm using the right tool (other vstroms can go down the same road and not bend a rim); but I think my tool may need either it's forks tweaked, or it's rider needs to figure out how to not hit invisible rocks...
Hardened and brittle are two different thing. Glass, rocks, concrete, cast iron are all hardened surfaces but they are also brittle.

I to think you are using the right tool for the job! Vstrom can do anything! Get a new wheel and get back up on that horse and show those rocks whos the boss!
 

·
Registered
Joined
·
652 Posts
Discussion Starter #11
Some thoughts:
  • My 705 is a Radial. The tire was at 35psi cold, before I ever hopped on it for this ride. I check it pretty regularly since I had the rim fixed 3 months ago, and it's always been right on.
  • Nobody I personally ride with lowers their tire pressure before hitting a dirt road. Mostly because we know we'll eventually be back on the pavement, and then the inconvenience of airing back up...no thanks. Looking back, of course, I suppose that lowering the pressure would have deformed the tire enough to cover the rim. But then would I have a huge gouge in my tire where it got squished between the rock and the rim? I dunno.
  • "Use the right tool" makes me chuckle; do none of you ride your vstrom on dirt roads? I think a pothole on a paved road would have done the same thing to my rim, so...would I then have been using the wrong tool to ride on the road? :ROFLMAO: Adv riding is a compromise. As I said, I think I have an OK tool; just need to fine tune it a bit since I really like riding on dirt roads.
  • If a rock could now explode my rim if it hits in that spot, I'm guessing a pothole or severe road irregularity could do the exact same thing.
  • So on Friday I'm buying a used front wheel off the same bike I bought my new-to-me motor from. 😁
I've got a message in to @RichDesmond to see if he can give me some pro advice on what to tweak in my forks to possibly prevent this from happening again.

For now, I'm still commuting on this bike, and it's holding up pretty well! Just a little concerning when the road gets rough. :)
 
  • Like
Reactions: rattlinjack

·
Registered
Joined
·
15,252 Posts
You can only work metal so much before the crystalline structure changes. Bull dozing a heavy bike through rough terrain tests the limits of it's components.
On a ride with other bikes my '08 BMW GS hit a pot hole 2 up and suffered no issues. Other BMW's with cast wheels had flats or bent rims. i had spoke wheels, no problem.
 

·
Administrator
Joined
·
5,757 Posts
Surely your front suspension is too firm and not absorbing the impacts. I also do not air down offroad - to protect my rims. I run 33psi always but will put it up to 36psi for long high speed open road trips. If you have put in firmer springs, thickish oil, and too much of it, you may have taken away the suspensions ability to deal with sudden impacts.
 

·
Premium Member
Joined
·
2,897 Posts
Some thoughts:
  • My 705 is a Radial. The tire was at 35psi cold, before I ever hopped on it for this ride. I check it pretty regularly since I had the rim fixed 3 months ago, and it's always been right on.
  • Nobody I personally ride with lowers their tire pressure before hitting a dirt road. Mostly because we know we'll eventually be back on the pavement, and then the inconvenience of airing back up...no thanks. Looking back, of course, I suppose that lowering the pressure would have deformed the tire enough to cover the rim. But then would I have a huge gouge in my tire where it got squished between the rock and the rim? I dunno.
  • "Use the right tool" makes me chuckle; do none of you ride your vstrom on dirt roads? I think a pothole on a paved road would have done the same thing to my rim, so...would I then have been using the wrong tool to ride on the road? :ROFLMAO: Adv riding is a compromise. As I said, I think I have an OK tool; just need to fine tune it a bit since I really like riding on dirt roads.
  • If a rock could now explode my rim if it hits in that spot, I'm guessing a pothole or severe road irregularity could do the exact same thing.
  • So on Friday I'm buying a used front wheel off the same bike I bought my new-to-me motor from. 😁
I've got a message in to @RichDesmond to see if he can give me some pro advice on what to tweak in my forks to possibly prevent this from happening again.

For now, I'm still commuting on this bike, and it's holding up pretty well! Just a little concerning when the road gets rough. :)
Here's what I sent the good Doktor:

"Well, I've seen the bent rim thread and the first thing that pops into my head is the old Henny Youngman routine.

Patient: Doc, it hurts when I do this...

Doc: Well, don't do that!!

:)

Seriously, this has nothing to do with the forks. The stiffer springs help, as does raising the fork oil level. Both things help prevent bottoming, which can occasionally be a contributor to a bent rim. Most of the time though, it's just hitting something too big too fast, and it's the inertia of the wheel itself that it generating the force. Thinner fork oil (10w) might help very slightly, but probably not enough to have made a difference,
The Strom isn't any kind of dirt bike. It's a street bike, pure and simple. On a scale of dirt-worthiness it's much closer to a Gold Wing than it is to a CRF450."
 

·
Administrator
Joined
·
17,101 Posts
These cast wheels are not fragile, my bud Craig abuses his 650 off pavement and has yet to mess up his wheels.
 
  • Like
Reactions: DesertBike

·
Registered
Joined
·
448 Posts
Trials bike riders are running 4-5psi rear and 7-10psi fronts (of course, they're using rim-locks to prevent tire or tube failure) and dual-sport riders are running 15-18psi For slowly picking your line through and over larger rocks, lower tire pressure can increase adhesion. For sure, these 500lb machines are road bikes with good manners off the beaten path and there are better choices for bouncing off rocks, but once you have big knobbies instead of road tires, lower air pressures have been used by many riders successfully. Tubeless spoked-rims are relatively new to the world and offer a good compromise, but true spoked-rims are generally tubed and allow for more reliable air-down work. YMMV
 
1 - 20 of 78 Posts
Top