My quest for a perfect Alta Redshift motocross suspension (Part 1)

[Mikec265]

Philip and MattB have officially cost me money..... My suspension is officially on the way to KTM World! I hope I can jump and turn my MXR with confidence like I can on my RM250. I believe in those on here who are smarter than I am to help us keep these bikes running. Worst case scenario couldn't a complete battery rebuild and electrical system rebuild/replacement be done to power the same motor? Like a new BMS, new cells, new controller, new throttle, and we should be back up and running if it's gotta go that far.

 

[Sumik]

Hello, if anyone in Europe needs help with suspension, I can provide the best address. They did upgrade 5 Alta already, maybe the largest number for a suspension tuner - coil conversion, trax update, aer, all no problem..View attachment 2209View attachment 2210

The best suspension tuning I have ever had!!

 

[Mikec265]

Just got off the phone with Glen at KTM World. Almost $1000, but I got a 7.0 rear spring and they had to replace some bent/ smashed some internal parts in the forks. Should turn with confidence and take some big hits
now. I hope I can test it out Thursday or Saturday.

 

[TCMB371]

7.0????? How heavy are you?

 

[Philip]

His spring rate recommendations are crazy. Ignore Glen, for your own good. Something is way off with his spring math, but his damping is spot on.

 

[Rix]

7.0????? How heavy are you?

When I had my XCF suspension revalved and set up by WR1 racing, I went to a 7.6 to 8.2 kg/mm progressive shock spring. Don't remember what the front was. My ready to race weight with everything on was 255 at the time, and was set up with A-racer skill/speed in the desert. I know I was heavy, but not WAY out of the ball park. I do know that shock to travel/ratios dictate alot of these factors, but 7.0 doesn't seem way out of the ball park, tell me what I am missing please?

 

[Philip]

When I had my XCF suspension revalved and set up by WR1 racing, I went to a 7.6 to 8.2 kg/mm progressive shock spring.

Does that XCF have a PDS shock without a linkage? That's the only way this spring rate would make any sense.

@Mikec265 -- If you are as fast and as heavy as Rix, I would then buy a 66 N/mm spring and bring it to the track with you, in case you can't ride your 7.0. Or a 63 N/mm if you are just slightly over 200 lbs.

 

[Mikec265]

I thought it was heavy, but hopefully I can try it at an arenacross track on Thursday. I basically told him amatuer supercross, and I like big safe jumps. 235 in gear. As long as I am no longer afraid of the forks pogo stick in and washing out in turns, and it will take some bigger hits I'll be happy. He said something about the linkage ratio needing heavier springs. Idk what the suggested fork air pressure is yet. Gotta open the box on Monday or Tuesday and find out. My track at home is basically going to be finished this spring as an amateur SX track with whoops ,timing sections and one big ass landing with 2 take offs. My buddy that runs the dozer is going to set up his rev 1 spec ramp on the big one. Currently it's just a timing section and one big 65 ft double. hope it's not too stiff, but I'm not a suspension guru.
The bike has made me faster, but I got to the point where I was just to afraid of the forks to pick up the pace anymore. I was bottoming on my kids peewee track because it was so soft.

 

[Philip]

Glen told me to run a 66 N/mm spring. I am running the stock 60 N/mm spring for motocross. I weigh the same as you.

Don't waste your $80 on a 7.0 spring, you'll never use it.

 

[TCMB371]

I'm pretty much a legit B rider and weigh 190lbs naked. I jumped up to a 6.4 spring and it feels much better. I'm also running 160psi in the forks with stock valving at the moment. The forks are definitely valved too soft for my skill level. I'll be stiffening up the compression here pretty soon.

 

[Mark911]

I wouldn't be too sure about 7.0 being way off. My suspension simulator shows with that rider weight it'll still be around 90mm race sag with about 5mm preload. That's in the ballpark if you plan on hucking big ass jumps.

 

[Mikec265]

I'll see how it goes. The spring is already being shipped back with the rest of it. I can't wait until the snow melts so I can polish off the rust and start improving my technique and skill some more. I didn't ride it as much as I should have last fall mainly because the suspension was so bad. I'm at 50 hours, hoping to put at least another 100 on it this year. I also gotta rig the rear fender bolts somehow. I rode in November when my track was as sticky and muddy as it gets. A few bolts/nuts pulled out of the plastic.

 

[Rix]

Does that XCF have a PDS shock without a linkage? That's the only way this spring rate would make any sense.

@Mikec265 -- If you are as fast and as heavy as Rix, I would then buy a 66 N/mm spring and bring it to the track with you, in case you can't ride your 7.0. Or a 63 N/mm if you are just slightly over 200 lbs.

Shit Philip, I totally didn't take that into consideration, yes it was the PDS shock, no linkage. Man, normally my head isn't this far up my ass.

 

[Mikec265]

7.0 spring and 162 psi at the local arenacross track yesterday felt great! I'll have to wait at least a couple weeks to see how it is outdoors. I'm definitely another fan of KTM World's suspension shop. Some fast outdoor turns, braking, and acceleration bumps will finalize my testing. Definitely feels great jumping, and plowing my front wheel into things on purpose.

 

[Philip]

I actually tested a 63 N/mm rear spring last weekend, up from my old stock 60 N/mm. It felt okay on a jumpy hardpack track. For loamy MX tracks, I think I would be going back to 60 N/mm.

I had to pump up the fork to 169psi to restore the balance, else the rear was kicking and the front was washing out or jackknifing on turn entries.

I am about 235-240 in gear, and I am a B-class rider on familiar tracks.

 

[snydes]

After putting it off for way too long, I sent my suspension to KTM World as well. The hype is justified, this bike feels better everywhere IMO. The guys at KTM World are also great to work with. Very professional. They clearly got it figured out on the Altas. Definitely recommend

 

[VINSANITY]

I’m using Phillips old KTM world suspension - definitely a major step up from stock MXR - what magic is inside - I really don’t understand what KTM World did