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Flat Track Wheel Size Selection MX Bikes, Track Lengths 250/450 DTX Singles Class

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Starting a thread to see if anyone out there has insights into wheel size selection for the standard Motocross Bike 250/450 DTX Class. 

It's becoming more and more popular lately go run DTX whether on actual DTX setups or even knobby class. I'm running into tons of people that are starting out because it's kinda hip and it gives an IN to racing to what many people feel that missed out on the motocross years. Also, the costs are much less then MX so MXrs are crossing over and new riders are going right in because used cheaper bikes can have good racing on tracks less then the mile. Personally, I love sliding sideways at speed and the TT is my favorite race in all of dirt riding. That being said, there's some legit setup questions especially about wheels since it's the first conversion before doing full setups with suspension. I rode a top racer's setup with 2.75" front and 3.0" rear on a 1/4 mile DT and it felt like turning a FatBoy, it stuck to the track, but wow did it turn stiff.

Things that are stated from the DTX wheel builders:

  • 19 inch are standard, local tracks often let Sumo wheels with FT tires, but AFT requires 19". 
  • AFT limits wheel size to 19 x 3.5 in maximum. No specified minimum width.
  • All around track size suggestion is: 19" x 2.15" to 2.50" for front || 19" x  2.75" for rear
  • Standard Flat Track Tires are 130/80-19 Front and 140/80-19 Rear
  • On shorter tracks, thinner wheels give the tire more roundness allowing for better maneuvering while on longer tracks the wider wheel make for a more flatter tire giving more contact area for acceleration, but hinders cornering. 

Where things are silly on paper. The various DTX tire makers give what they say are the recommended/minimum wheel widths. It seems people don't exactly follow them. for example Shinko says min wheel width for the 130/80/19 is 3.0 and the 140/80/19 is 3.5 . I see people run them on wheels not that wide at all.  for other brands:

589697038_maxxisdtr1.JPG.f6468985c1c34801690558c33b0d4108.JPG

1605000372_dunlopdt3.JPG.e9e1ed81090a46d6fee8d1ea731259c1.JPG

Add in here, gearing, i run my standard 13/50 MX gearing, i 4th gear on the 1/4 mile. I don't have the greatest pull on the straightaway but it is great in corners. On the TT couse, stock gearing feels perfect. I have not put my aggressive coupler on the bike yet, i'm waiting to get things setup and tweaked right before throwing a different power setting. I'm running a stock 2019 RM-Z450 for what it's worth. 

 

What are people running and or opinions on wheel widths for different track sizes? 

What sprocket sizes are people running on different tracks?

 

BTW to ask, any chance of mods putting in a Flat Track/TT category since tons are running over to the sport and thy're all thumpers?

 

Edited by vortexsophia

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4 hours ago, William1 said:

Less than a dozen TT members are active in flat track. For example, TT had a street bike section. Quiet as a church on a Saturday night. Gone.

Out in the Pacific North West, Flat Track has become a new hip trend. We have places like See See's out here where they build custom bikes, sponsor and support locals to race in all different categories and moto race styles, etc. It's where you get coffee and also see the rebirth of the Super Hooligan and the re-emergence of the sport. I was raised by old school flat trackers from the 70's and have rode and raced most forms dirt, sliding by that wall at speed is hairy and tends to terrify everyone more then MX. Seems more popular on the west coast and like maybe CT/Western MA by Limerock and New Haven.  The TT track has effectively been redefined as "all dirt Supermoto", since the track layout is about the same and you can run Sumo setup as long as you have DTX tires on those 17's. Also, you got a lot of girls up in coming in the sport and are dominating, so the older people are going to start seeing a lot more of us.

 

That being said, someone will chime in on this eventually that actually knows what they are talking about in the race style. If not i'll add info to make a detailed data set. 

Edited by vortexsophia

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I'm curious where you have been riding. Based on your location I would guess you are referring to Castle Rock? Gearing is something you will have to play with since there are a ton of variables but I would suggest gearing the bike to run 3rd gear on a 1/4 mile (Castle Rock is probably a little bigger than a 1/4 mile but smaller than the 3/8 mile it claims to be). When I raced Castle Rock on my 06 CRF450R I ran 14/48 on the oval in 3rd gear. I ran the same on the TT only because I suck at TT's and gearing was the least of my problems. Plus with Castle Rock (or I guess a lot of grove tracks) you rarely get the same track conditions from one race to the next and if you're not careful you will end up chasing your tail when it comes to gearing. Meaning it could be dry slick in practice and tacky in the main when the sun goes down and the water starts to come back up. 

I'm no pro but I have won plenty of races in the Vet classes at Castle Rock and Salem running Dunlops, Mitas, Maxxis all on either 2.15 or 2.50 Warp 9 wheels front and back. I say I'm no pro because, well I'm not, but mostly to state that while I am a decent rider I'm not sure I would notice much difference in rim width. Getting gearing dialed in is what has helped me the most. Opinions vary but I gear my bike to be on the rev limiter coming in to the corner and it helps me get set up/slowed down for the corner immensely. 

Anyway I'm just babbling on with no real advice to offer. I just thought I would pop in and see where you have been riding. I'm in Idaho but my dad lives in South Western Oregon and still races.  

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4 hours ago, EKhatch said:

I'm curious where you have been riding. Based on your location I would guess you are referring to Castle Rock? Gearing is something you will have to play with since there are a ton of variables but I would suggest gearing the bike to run 3rd gear on a 1/4 mile (Castle Rock is probably a little bigger than a 1/4 mile but smaller than the 3/8 mile it claims to be). When I raced Castle Rock on my 06 CRF450R I ran 14/48 on the oval in 3rd gear. I ran the same on the TT only because I suck at TT's and gearing was the least of my problems. Plus with Castle Rock (or I guess a lot of grove tracks) you rarely get the same track conditions from one race to the next and if you're not careful you will end up chasing your tail when it comes to gearing. Meaning it could be dry slick in practice and tacky in the main when the sun goes down and the water starts to come back up. 

I'm no pro but I have won plenty of races in the Vet classes at Castle Rock and Salem running Dunlops, Mitas, Maxxis all on either 2.15 or 2.50 Warp 9 wheels front and back. I say I'm no pro because, well I'm not, but mostly to state that while I am a decent rider I'm not sure I would notice much difference in rim width. Getting gearing dialed in is what has helped me the most. Opinions vary but I gear my bike to be on the rev limiter coming in to the corner and it helps me get set up/slowed down for the corner immensely. 

Anyway I'm just babbling on with no real advice to offer. I just thought I would pop in and see where you have been riding. I'm in Idaho but my dad lives in South Western Oregon and still races.  

Thank you for the reply, this is the kind of info I was hoping for. Yeah, I'm running Castle and Salem. After the summer i'll probably start doing some of the CA circuit as well. I normally spend time practice on the Hollister TT since being on the West Coast and i can just sit on it all day and powerslide the sweeper and hone in right hand sliding. Normally i've practice either knobby or on my 650R sumo, but as my BRP gets older, the aftermarket dwindles and there's no really good class that the bike fits into aside from Open Amature FT, Baja or say China Hat, perhaps this is why the bike was discontinued in the long run.

Back to the dirt track. The racer's bike I rode was 450 DTX with 2.75 front and 3.0 rear, he told me to just run the whole track in 3rd. So I totally see what you mean with the gearing. As for the wheels, those wheels were so stiff to turn that i though it was too much on what i feel is a small track, I could feel it being right in a 1/2 mile or more. If 2.15s and 2.5s worked well for you knowing both tracks, buying either of those from Warp 9 (my sumo has them) are cheap and quick. Add that if I want to be really cheap i can just buy a 2.5 rim and spokes and lace the stock rear to front, but i'm just going to build a fresh second set. The 2.75s and up start costing a penny for the rims and that's where I wonder if it's all worth it. were you running both front and back 2.15s and 2.5s or did you switch up and have the smaller on the front? Somehow, i can see Salem making use of smaller wheels. the difference between them i can imagine is hard to tell, but way wider wheels feels noticeably stiff.

Edited by vortexsophia

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I actually have one set front and rear that are 19x2.15 and one set that are 19x2.5. I know that sounds dumb but let me explain. lol

I put the bike together in a rush to make it out to Castle Rock years ago and surprise my dad who I hadn't raced with in about 15 years and when I did the shop that helps me out couldn't get the 2.5's from Warp 9 because they were out of stock and Sun rims are just way too dam expensive for a novice rider such as myself. 

Later down the road when I decided to build a second set of wheels I got the 2.5's and I didn't really want to spend the time and money to take apart and re-lace the first rear wheel and since I already had the hubs I just got the 2.5's set up for another front and rear set. 

I'm not sure it matters what you run at Salem. That place is so badd ass. On a half decent night there is traction everywhere. 

If you have ran out at Salem very much you have probably seen my dad. He used to be hard to miss because his bike and leathers were Subway (the sandwich place) themed because he used to be sponsored by the local Subway in his town.  

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Does Brian Bartlow make it to the tracks up there? He is a nor cal guy that rents out bikes and teaches flat track classes. It’s a great way to find out if you want to do it before you invest in setting up a bike.

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Well this thread is going as well as William predicted. lol

You going to race in Pendleton this weekend? I'm not racing this year but I'll be there as an event photographer. 

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On 7/10/2019 at 8:31 PM, bk29 said:

Does Brian Bartlow make it to the tracks up there? He is a nor cal guy that rents out bikes and teaches flat track classes. It’s a great way to find out if you want to do it before you invest in setting up a bike.

I had a local track winner let me spend time on his bike (450DTX) that he wins everything with out for a whirl. I am in the quest now for the conversion. The thing is, for how little time gets put on the bikes, i wonder if i just buy a used 450DTX already converted and keep my new '19 RM-Z450 stock for all around riding MX, GP and TT racing. I missed lats week's race due to lack of sleep. I was up all night pondering buying a like brand new Harley 883R that had all the chain conversions and wheel upgrades done to it on a new engine. I ended up buying the ready (minus front number plate) Tracker Hooligan. Still going to stay with 450DTX, but i love the 70's Hooligan throwback aesthetic as well. I'm going to do the See See style Hooligan front plate with the flat light bar headlight cutout. Number stickers on Oil/Battery covers. I had to sell the BRP for this, but, i get more miles out of this setup then the BRP as sumo conversions.

harleyhooligan.jpg

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On 7/16/2019 at 12:24 PM, EKhatch said:

Well this thread is going as well as William predicted. lol

You going to race in Pendleton this weekend? I'm not racing this year but I'll be there as an event photographer. 

Actually, this thread is going great, the content quality was worth it. My next race will be what was supposed to be "The Wild Ones" but was hybrided as another event name, still club races on friday and the party race event on saturday with bands at Castle. 

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Has anyone ran 2.15 front and rear ? Completely new to flat track and trying to dip my feet before I dive in money wise. I have a 2016 kx450f. I was just going to lace a rear rim on the front hub ? Does anyone know if the rear spokes would fit the 19 inch rim on the front hub ?

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I've ran 2.15 front and rear many times with all the different tires (Dunlop, Maxxis, Mitas) on cushion track and blue groove. Sure they may not be the ideal width rim but I've never had any problems. Getting the suspension lowered/set up correctly is way more important than spending extra money on wheels. 

 

Sorry, not sure on the spokes question. On my Honda the front and rear have a different spoke count so that wasn't really an option for me. 

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Cool thanks for the info! Another thing what does everyone think of boghner racing for the suspension. I’m located 30 min east of Indianapolis, Indiana. I’m trying to budget build but want reliable suspension... I’m on the air forks as well. I wish I had the knowledge to do it my self. Does anyone know where I can get the suspension done around Indiana and affordable price ??

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You should sign up to the group Flat Track Shop and Swap on Facebook and ask. Since Flattrack.com no longer exists it's a good place to ask questions and pick up some good deals on some used parts. I don't know anything about Boghner suspension but I've seen several sets of forks for sale they did. Or at least had their stickers on them. lol

 

https://www.facebook.com/groups/357166127665643/

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You mentioned running supermoto wheels, what tires would you run? I'd like to try some flat track without spending a ton. Could run either 16.5 or 17 front, 4.25 or 5 rear.

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4 minutes ago, toten said:

You mentioned running supermoto wheels, what tires would you run? I'd like to try some flat track without spending a ton. Could run either 16.5 or 17 front, 4.25 or 5 rear.

Rain slicks.

 

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