Sumo Conversion

[Jewcati]

I have a Husaberg FE 390, for dirt. I am thinking about doing a supermoto conversion, but I would like to be able to switch back and forth, how much does a supermoto conversion cost, and how do I handle the suspension issue going between dirt and street?


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[Tricky Mike]

how do I handle the suspension issue going between dirt and street?

More importantly is the front end geometry issue going from 21" to 17"
You really need new (reduced offset) triple clamps.

[loudbeard]

It all depends on what your goals are. Do you want the sumo to be something to whip around town or a track weapon? If it's the former, easy. About $1,500 gets you a set of 17's complete with discs, sprocket, tires, and caliper relocation bracket. That's more than enough for clowning around.

If you want a real track weapon, you'd be better off to get a second bike.

[Jewcati]

It all depends on what your goals are. Do you want the sumo to be something to whip around town or a track weapon? If it's the former, easy. About $1,500 gets you a set of 17's complete with discs, sprocket, tires, and caliper relocation bracket. That's more than enough for clowning around.

If you want a real track weapon, you'd be better off to get a second bike.

Ah....

Second option...good to know, seems that way


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[loudbeard]

Ah....

Second option...good to know, seems that way

Right on. Like Tricky said, the geometry isn't going to be right when you go from a 21" to 17" front wheel you're decreasing your trail to a degree that isn't safe when pushing the limits. The other negative against this bike is the PDS rear suspension. The bottom of the shock is bolted directly to the top of the swing arm rather than a traditional linkage system. Works well in the woods, but not so much on a race track. That's just the geometry aspect. Then you have the suspension settings. Road racing and woods are so far apart you wouldn't be able to just spin the clickers and get it close. It'll be several spring rates off and the valving will be way too soft.

So yeah, this bike would do perfectly fine to hop curbs and do whoolies, even go have some fun at a track day if you take it easy. A racer she is not.

[Jewcati]

Right on. Like Tricky said, the geometry isn't going to be right when you go from a 21" to 17" front wheel you're decreasing your trail to a degree that isn't safe when pushing the limits. The other negative against this bike is the PDS rear suspension. The bottom of the shock is bolted directly to the top of the swing arm rather than a traditional linkage system. Works well in the woods, but not so much on a race track. That's just the geometry aspect. Then you have the suspension settings. Road racing and woods are so far apart you wouldn't be able to just spin the clickers and get it close. It'll be several spring rates off and the valving will be way too soft.

So yeah, this bike would do perfectly fine to hop curbs and do whoolies, even go have some fun at a track day if you take it easy. A racer she is not.

In all fairness...neither am I


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[Tricky Mike]

Years ago I did exactly what you're describing with a KTM 520... Even had no-link rear suspension.

I got a set of wheels, caliper bracket, etc... Took it up to the track and took it real easy. Still crashed.

The combination of no front end feel and wide MX handlebars is a really effective recipe for front tuckage.

If you just want to tool around on the street a bare bones conversion *might* be ok, but to be honest I wouldn't do it. Less so if you plan on bringing it to the track.

[Kurlon]

Are you going to race, or just hoon it up on the street?

If not racing, do a 'sportsman' setup, stock size wheels with road rubber. Don't bother changing anything else, minimal cost and you will be able to push harder than you'd expect. Slightly higher expense, score a used set of stock wheels to make swapping easier.

[nhbubba]

It all depends on what your goals are. Do you want the sumo to be something to whip around town or a track weapon? If it's the former, easy. About $1,500 gets you a set of 17's complete with discs, sprocket, tires, and caliper relocation bracket. That's more than enough for clowning around.

If you want a real track weapon, you'd be better off to get a second bike.

This, all day.

Also realize virtually nothing in super-moto land just "bolts-up". It is the land of dicking around with parts half-tested together. If you are not mechanically inclined and not willing to tinker you had best plan on paying someone else to build the super-moto for you. And building a bike that goes both ways is probably out of the question.

[nhbubba]

If not racing, do a 'sportsman' setup, stock size wheels with road rubber. Don't bother changing anything else, minimal cost and you will be able to push harder than you'd expect. Slightly higher expense, score a used set of stock wheels to make swapping easier.

Honestly, this is what I would do as well. 2nd set of dirt sized wheels with the most street friendly rubber you can find.
Or sell the dirt bike, buy a factory supermoto, a 2nd set of 17's and fit with pseudo knobs. TKC80's now come in 120 profile 17" sizes.

Gearing and brakes will be easier to deal with, for starters.

[loudbeard]

Years ago I did exactly what you're describing with a KTM 520... Even had no-link rear suspension.

I got a set of wheels, caliper bracket, etc... Took it up to the track and took it real easy. Still crashed.

The combination of no front end feel and wide MX handlebars is a really effective recipe for front tuckage.

If you just want to tool around on the street a bare bones conversion *might* be ok, but to be honest I wouldn't do it. Less so if you plan on bringing it to the track.

I guess the 520 already has very little trail. Probably a reasonable guess that his Berg is similar. Also probably a reasonable assumption that enduro bikes in general are setup to favor quicker turning in lieu of higher speed stability, making them risky motard conversions. Most 450 MX bikes are rideable with a simple conversion, although anyone taking it seriously is definitely into a set of offset triples.

[Jewcati]

Thanks guys. Just trying to get back to the track on a budget.

This is probably not the answer


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[Kurlon]

If you're not racing, a sportsman setup will get you on the track quite happily. Hell, I raced at NHMS on a bone stock 92 brake system and clamps* and it didn't really hold me back. The rotor was pissed and turned into a bowl when I went to unmount it from the wheel, but had I left the bolts in place it would have continued to work.

*Old YZ geometry != KTM Geo. Similarly CRF Geo != KTM Geo, etc...

[loudbeard]

Cheap and motard are not really used in the same sentence. Just go up to NHMS during the next round and buy one of the 13 SV's parked next to the crapper.

[maxim_X]

What everyone else said is pretty accurate. I'll add expect to spend $5k-$10k to get something competitive from a regular dirt bike, probably closer to the high number. They are pretty expensive to keep running too.

[MattR302]

I’m doing something similar with my DR650/790. I’m keeping it realistic with my goals though. Sumo wheels for street and occasional (slow yellow group) track days, and stock wheels with 50/50 tires for dualsport/light ADV rides. I picked up a used set of Warp 9 sumo wheels with oversized front rotor, caliper bracket, rear rotor, and cush drive hub. Just installed them for the first time last weekend:

-Having sprocket sizes that work with the same chain help make for an easier swap back and forth.
-Also having the same size front rotor - on the DR, swapping the caliper relocation bracket means you have to remove the brake pads. I’ve only done it once, but I’m thinking it may just be easier to swap the big rotor over to the 21 rather than swap the caliper bracket.
-My 17” front wheel has the tabs to drive the factory speedometer cable, but then the speedo/odometer end up reading about 30% faster. They make aftermarket speedo drives to correct this, or you could swap to an aftermarket speedometer (if you even care).

When I had my DR350, I had a second set of stock wheels that I put Shinko 705 tires on for street duty, they’re like a 85/15 street/dirt tire. They stuck plenty fine for street twisties, wore like iron, and were ok for exploring dirt and gravel roads. I even did a Thompson non-sportbike track day on them. If you can get a stock set of wheels cheap, I’d just go this route.

[JettaJayGLS]

Back in my day...a lot of people raced relatively stock CRF450s.

Mine was an 02. Stock clamps, revalved stock suspension. Didn't take all that long to find 21s. Will you get an expert podium, eh, probably not. Then again, previous owner of my race bike could do 18s on it.

Wheels, something to help it stop, and go rip it on or off the track. I don't know much about the Husabergs, but if it is similar to 17 year old mx tech, it should be plenty of fun on the track. Simple motards are incredibly forgiving and easy to ride, in my mind.

As others have alluded too, its the motors that make motards expensive to use as a dedicated track bike. It definitely isn't the chasis. Cheap fun is an SV650. A middleweight ain't all that expensive either if you either a) aren't super fast, or b) can take a step back and not be full gas all the time.

I feel like I did 90% of the damage to my tires in 10% of the laps while running trackdays on a middleweight.

[nhbubba]

Preface this by knowing that I am a slow, not incredibly experienced rider. I've probably never ridden a really dialed in machine.

I never thought the front end on my converted DRZ400 was that bad. That bike started as a S or dirt model and I fitted DRZ400SM 17" wheels to it.
The WR450F conversion I have now is a little light on front end feel. But I find it perfectly ridable at a yellow group pace. I'm sure triples would help. But I agree they aren't necessary for recreational fun.

The issue is the easy dirt <=> sumo mode conversion. IMO that requires a lot of compromises and just isn't worth it.

Buy a dedicated track toy. Keep the FE390 just as it is.. or sell it.

[maxim_X]

Back in my day...a lot of people raced relatively stock CRF450s.

Mine was an 02. Stock clamps, revalved stock suspension. Didn't take all that long to find 21s. Will you get an expert podium, eh, probably not. Then again, previous owner of my race bike could do 18s on it.

There are a couple of freaks out there, like Narbone, but other than those the fast motards are only going 18's these days. For me the difference between an 18 and a 21 is HUGE, and the machine alone could make the difference. I'm not saying it's not worth having a motard if you can't do 18's on it, but once you race one that's really setup anything else is kind of scary.

[JettaJayGLS]

There are a couple of freaks out there, like Narbone, but other than those the fast motards are only going 18's these days. For me the difference between an 18 and a 21 is HUGE, and the machine alone could make the difference. I'm not saying it's not worth having a motard if you can't do 18's on it, but once you race one that's really setup anything else is kind of scary.

Oh yes, 21s and 18s is a HUGE difference. 21s also put you at the front of track days and that was the vibe I got. That said I’m still not recommending a motard for cheap fun.

[breakdirt916]

naah I've "tried" some of these combos, and I didn't like sportsman on a track because you couldn't push and the braking sucks...the geometry discussed is important in a track setting...swapping wheels/tires also kinda sucks if you do it often...and I've always subscribed to separating the duties and found aplated dual sport + dedicated street (or in your case track) bike is the best way. At best, the oem sumo option Nhbubba mentioned with a separate set of 17's w' "dirt" tires will keep everything working the way it's supposed to.

[Kurlon]

Well, no shit braking and cornering isn't as good on a sportsman setup as a full on ready to rumble no limits sumo build! Did you know the brakes on a Ninja 500 suck compared to a S1000RR? Blew my mind when I learned that!

If we're talking track days, not racing the goal is to find and then work maximizing the limitations of the bike. A sportsman setup gets you out there, a full blown conversion with wheels plus, or a second bike may break the bank meaning... no track day at all. If those are my choices, I'll try the one that lets me get a taste first, then if I catch the bug go balls deep.

One other note, I find the guys that come from road racing to Sumo have a much harder time with front end geometry not being spot on perfect, etc compared to the dirt / flat trackers trying Sumo / road racing. The latter you can put on a steaming pile with geometry that'd make Peter Kates run screaming and they'll still have a good time while showing up many riders who thought they were 'fast'.

[tls25rs]

One other note, I find the guys that come from road racing to Sumo have a much harder time with front end geometry not being spot on perfect, etc compared to the dirt / flat trackers trying Sumo / road racing. The latter you can put on a steaming pile with geometry that'd make Peter Kates run screaming and they'll still have a good time while showing up many riders who thought they were 'fast'.

[breakdirt916]

Well, no shit braking and cornering isn't as good on a sportsman setup as a full on ready to rumble no limits sumo build! Did you know the brakes on a Ninja 500 suck compared to a S1000RR? Blew my mind when I learned that!

If we're talking track days, not racing the goal is to find and then work maximizing the limitations of the bike. A sportsman setup gets you out there, a full blown conversion with wheels plus, or a second bike may break the bank meaning... no track day at all. If those are my choices, I'll try the one that lets me get a taste first, then if I catch the bug go balls deep.

One other note, I find the guys that come from road racing to Sumo have a much harder time with front end geometry not being spot on perfect, etc compared to the dirt / flat trackers trying Sumo / road racing. The latter you can put on a steaming pile with geometry that'd make Peter Kates run screaming and they'll still have a good time while showing up many riders who thought they were 'fast'.

lol you know me man, if I can get out there at the lowest possible price point (especially if it's investigative or novelty experience), I'm all for it! but the more bikes I ride, the more I've (high level) experienced the gradient, and quality of enjoyment from purpose built machines vs. the compromise of all-in-one versatility. if I was going to recommend it to anyone else, I'd say just get it done right and split 'em up. with how cheap track bikes are out there, an sv650/ex500 would be way more fun, safe, convenient and possibly cost efficient than a separate sumo setup on a oem dirt bike.

but yeah, if it's barebones cost, and the difference is getting out there vs. not at all, then yeah, give it a whirl.

I dunno who jewcati is - I just assume everyone out there is a track day/racer. @ OP - what's your track experience history and what are you looking to get out of it?

[loudbeard]

with how cheap track bikes are out there, an sv650/ex500 would be way more fun

Under no circumstances should anyone buy an EX500. It is a birth control bike. Yes, they can rail, but they are without a doubt the ugliest thing you will ever see at a racetrack. The price gap doesn't even justify it anymore.