So has anyone seen a Sunday, Socom, V10 or what have you, running a DHX air yet?
I haven't seen a pick of any yet but figure they must be out there.
I haven't seen a pick of any yet but figure they must be out there.
Bad ideas and dumb builds
- Thread starter 4xBoy
- Start date
my buddy is considering getting the new evolver air shock for his v10.
why is this a bad idea?
why is this a bad idea?
Good bad I don't know,
I wasn't coming up with a good thread title.
I wasn't coming up with a good thread title.
a sunday with a dhx air is a bad idea. someone rode one at diablo last year. after 1 run it was really hot. not a great idea for a full dh bike. imo
Air shocks overheat, making their seals expand and let all the air out.
If a seal expanded, it would get tighter around the shaft. If it contracted, it would get looser. All shocks heat up on DH bikes. Go ahead and grab an coil/oil shock's resi at the end of a run. If you have an avalanche, wear a glove.
The air shocks are IDENTICAL for damping issues, and will heat up exactly the same as a coil shock. The only difference is the spring mechanism (air instead of steel). The air cylinder itsel'f may heat up a little bit, but nowhere near what the oil resi will (on either type).
Exactly, although the DHX air has a few issues that cause it to not work so well for DH anyways.
Anyways, the problem is loss of damping, not air.
Also, a seal expands both ways. The ID gets smaller and the OD gets bigger, therefore, it gets tighter. In a properly engineered shock, suspension rated seals won't be doing this anyways, so it's a moot point.
Todd tested one on his Sunday last year for one race at Diablo I'm pretty sure. The shock body was so hot you could barely touch it after a few runs... pretty nuts.
Both of Sam's Sundays had a DHX Air on it for the Otter last year - but that track is so smooth, overheating isn't really an issue I guess.
Both of Sam's Sundays had a DHX Air on it for the Otter last year - but that track is so smooth, overheating isn't really an issue I guess.
I have a float on my V10 no problems at all
Ahahahahaha
I had a friend try and tell me to go air for my Gemini DH needless to say there will be a DHX 5.0 on it soon.
one of my friends is running a dhx air on his m3. that thing is f-in dialed.
sam hill runs dhx air quite a bit. I suppose if i could put on a brand new shock after each practice run and have those caliber of techs to tune it for me I would too.
other dumb builds....where is the picture of the Chumba or whatever will the swiss cheese e.13 taco?
other dumb builds....where is the picture of the Chumba or whatever will the swiss cheese e.13 taco?
mattmatt overheating isnt the problem that air shock incounter on a dh bike, or any other bike for that point. now i dont know the whole engineering side behind all of this and why air shocks like to do this, but they have a bad tendency to blow threw travel and lock out at full compression (dhx air's especially). i dont know if there was a bad run of them or if its just to much for them to take but they will lock up and well obviously cause the bike to ride like crap. now i know its not a highly engineerd post and i kinda contradict myself, but im just saying they can be used for dh, but i wont use one just for these reasons.
I'm curios what are they...and why do they happen. I don't really understand. It makes sense to me that things get hot and why an air shock would get much hotter than a coil over, but what causes fade...?
pics? i though fox dont make the float in the 8.75X2.75 size? otherwise i want one!!!!
this line of thought is just dumb
it wasnt a taco i dont think stephen.
EDIT: nope, it wasnt
oh yea, and he stated 36lb, lol
I think dh kid weighs like 120, so if anybody could get away with it...
Huh?
Yes it is. A hot air shock increases pressure since you're relying on a pressurized gas for suspension. A fixed volume gas increases in pressure with heat. And dampers, on an air OR coil shock lose a bit of damping as the fluid gets hot and thins a bit.
Isn't that called bottoming out?
ding ding ding ding
and even tho the dhx air has all the bad rep with over heating, the rp23/ float doesn't. also since i run very little bottom out on my bike i could use an air shox for more then just the smoothest courses.the air pressure increasing is one of the problems, but with the dhx air when it overheats too much it looses all damping.
and it loses some damping too
is the rp3/dhx air/air, or air/oil?
Just run a Cane Creek Double Barrel and be done with it!
nope. that would be a smart idea. this is the dhx air thread.
ohh okay kidwoo i guess i just misunderstood, and about the lock out thing it is bottoming out, but when you bottom out the shock will come back. with a dhx they tend to lock up when you bottom them out, or atleast that is what i keep hearing about them.
and then have to be sent back to fox because if you try to take them apart they explode in your face and rip your fingers off.
Would an Isis Evolver be a better choice for a long travel application?
In my experience.......If you are running more than a 400 lb spring on your current setup or you weigh more than 170, you won't want to run an air shock. You either weigh too much or your bikes levarage ratio is too high and you will blow through the travel on big hits. Sunday's have one of the lowest leverage ratios in the biz, thus the occaisional use of an air shock. You should all consider that different people have dif. styles and ride dif. stuff.....you might haul ass down your local trail but if you dont ever go big or hit any hard g-outs, the air will work better for you than some guy that rides bridges and drops all the time. DHX 5 air's had a problem a while back with the seals which caused them to stick down but its all good now. Later,
Zeb
Zeb
i noticed that when i had 2 leverage settings on my bike (2.6:1 and 3:1) the more leverage the smoother it was. it was very very noticable. i think that the old vanillas or even the new ones with no platforms of any kind with a ti coil would be such a nice alternative. then having them pushed. ouulala!
That's because the higher leverage ratio makes the spring effectively softer. With the adjusted spring rate, the lower ratio will feel better.
i wouldn't hesitate to run one if i had a lower leverage ratio, damn 9.5
I ran a air shock on the back of my imperial last year at diablo and had no overheating nor loss of dampening problems whatsoever
This thread is a total rumour mill!
Seriously - "loss of all damping" when an air spring heats up? that's a freakin joke - a couple people really need to think before they post.
1. The 07 DHX has the sticking down seal issue all sorted out, and even on previous years - performing air sleeve maintenance can both prevent and cure the problem (when or before it occurs). The manual recommends it every 40 hours of riding, and it's not that hard.
2. Fox actually provide manuals with pictures and videos on how to do this, and also sell the full seal kit to service the air sleeve.
3. Damping can't drop off mid stroke! The damper in the DHX Air works the same as it does in the DHX coil, and the only thing that will really affect the damping is the heat generated by the damping itself in the damping oil (so as transcend pointed out, damping characteristics should be very similar to the coil shock). Air sleeve heat isn't going to make a considerable difference here, and keep in mind that shock oil has a very high viscosity index meaning it will hold its viscosity fairly well over a temp range. More info in the last two paragraphs here.
4. The sunday (mapped in linkage) has a progressive to regressive rate. I know dw likes to call it progressive to linear, but he's yet to post a graph to disprove the one that came from linkage. In any case the progressive to regressive curve gives a lower leverage ratio in the middle of the travel, which should give more damping and a higher springrate in that portion of the travel. So even if the air spring itself did have some falloff in the middle (due to the crossover between pos/neg air springrate), the sunday should cancel that out fairly effectively with its leverage ratio curve. Finally the fairly low leverage ratio of the frame (2.6:1) is an obvious plus for air shocks, especially if you are a smaller guy.
5. The gemini DH is another killer candidate for an air shock. With a leverage ratio of 2.2:1, the numbers tell the tale.
6. One negative that you will get on an air suspension (that isn't an internet rumour that gets doubled everytime it's passed along) is that as air is compressed it expands, so it will increase the springrate slightly as the air gets hotter. Although I doubt it's a huge issue on most 2-4min tracks, as the negative air chamber auto regulates to suit the increased positive air pressure. For tracks over 4min (especially rough ones) it may be handy to keep the old coil shock in case you do notice the springrate changing. But for anything below it should be ok.
Seriously - "loss of all damping" when an air spring heats up? that's a freakin joke - a couple people really need to think before they post.
1. The 07 DHX has the sticking down seal issue all sorted out, and even on previous years - performing air sleeve maintenance can both prevent and cure the problem (when or before it occurs). The manual recommends it every 40 hours of riding, and it's not that hard.
2. Fox actually provide manuals with pictures and videos on how to do this, and also sell the full seal kit to service the air sleeve.
3. Damping can't drop off mid stroke! The damper in the DHX Air works the same as it does in the DHX coil, and the only thing that will really affect the damping is the heat generated by the damping itself in the damping oil (so as transcend pointed out, damping characteristics should be very similar to the coil shock). Air sleeve heat isn't going to make a considerable difference here, and keep in mind that shock oil has a very high viscosity index meaning it will hold its viscosity fairly well over a temp range. More info in the last two paragraphs here.
4. The sunday (mapped in linkage) has a progressive to regressive rate. I know dw likes to call it progressive to linear, but he's yet to post a graph to disprove the one that came from linkage. In any case the progressive to regressive curve gives a lower leverage ratio in the middle of the travel, which should give more damping and a higher springrate in that portion of the travel. So even if the air spring itself did have some falloff in the middle (due to the crossover between pos/neg air springrate), the sunday should cancel that out fairly effectively with its leverage ratio curve. Finally the fairly low leverage ratio of the frame (2.6:1) is an obvious plus for air shocks, especially if you are a smaller guy.
5. The gemini DH is another killer candidate for an air shock. With a leverage ratio of 2.2:1, the numbers tell the tale.
6. One negative that you will get on an air suspension (that isn't an internet rumour that gets doubled everytime it's passed along) is that as air is compressed it expands, so it will increase the springrate slightly as the air gets hotter. Although I doubt it's a huge issue on most 2-4min tracks, as the negative air chamber auto regulates to suit the increased positive air pressure. For tracks over 4min (especially rough ones) it may be handy to keep the old coil shock in case you do notice the springrate changing. But for anything below it should be ok.
Now I know people are going to start shooting those down one by one, but before you do - consider if you've actually tuned the shock to suit yourself, run on a low leverage ratio frame, and decided what you think of it rather than regurgitating other people's opinions.
I know if I run one, i'll probably rebuild it at some stage with the highest VI fluid I can find (silkolene or redline), make sure air sleeve maint is done regularly, spend time tuning with different amounts of oil in the air sleeve to fine tune the air volume and therefore air springrate (as some people on here have done) and in general - give it a fair go!
In return for a little effort and patience you'd reap a few benefits -
1. Infinitely tuneable springrate, handy if you are between available coil springrates
2. Easy to retune for different courses or riding styles.
3. Half the weight of a comparable coil shock with steel spring, at least 2/3 of the weight of a comparable coil shock with ti spring (and at less cost)
I know if I run one, i'll probably rebuild it at some stage with the highest VI fluid I can find (silkolene or redline), make sure air sleeve maint is done regularly, spend time tuning with different amounts of oil in the air sleeve to fine tune the air volume and therefore air springrate (as some people on here have done) and in general - give it a fair go!
In return for a little effort and patience you'd reap a few benefits -
1. Infinitely tuneable springrate, handy if you are between available coil springrates
2. Easy to retune for different courses or riding styles.
3. Half the weight of a comparable coil shock with steel spring, at least 2/3 of the weight of a comparable coil shock with ti spring (and at less cost)