Converting from bmx

PB Forum :: Dirt Jumping & Street
Converting from bmx
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flag travis-ridesbikes
Posted: Jan 27, 2015 at 22:13 Quote
so ive been really bored with bmx recently just i feel like the bike is to small and would like something bigger i 270 ed my ride to school bike the other day(http://websta.me/p/893056637191991987_275567187) clip im quote proud of that 270 because well that bikes stand over is huge

Now to the real thing im 6 ft still growing 150 lbs ride a 21.25 tt in bmx with 8.75 rise bars ive got bar spins locked trucks all that fun stuff Smile . i will mostly be riding park, street with bmxers and occasionally dirt (not much in SD) im not really scared of big stuff i might very rarely do some very minor downhill on it. Mostly going to be tricks.

1. what size should i go i was thinking 26 but im not sure
im buying used so what things are important double wall rims and sealed hubs ae a given but what about forks and frame regarding material.(id like front suspension)
2.how much would a bike like this cost used of course
3.just pretty much give me a general description of stuff

thank you in advance
flag cmc4130
Posted: Jan 28, 2015 at 9:31 Quote
travis-ridesbikes wrote:
so ive been really bored with bmx recently just i feel like the bike is to small and would like something bigger i 270 ed my ride to school bike the other day(http://websta.me/p/893056637191991987_275567187) clip im quote proud of that 270 because well that bikes stand over is huge

Now to the real thing im 6 ft still growing 150 lbs ride a 21.25 tt in bmx with 8.75 rise bars ive got bar spins locked trucks all that fun stuff Smile . i will mostly be riding park, street with bmxers and occasionally dirt (not much in SD) im not really scared of big stuff i might very rarely do some very minor downhill on it. Mostly going to be tricks.

1. what size should i go i was thinking 26 but im not sure
im buying used so what things are important double wall rims and sealed hubs ae a given but what about forks and frame regarding material.(id like front suspension)
2.how much would a bike like this cost used of course
3.just pretty much give me a general description of stuff

thank you in advance

I also switched from BMX a while back. For riding park and street, you might want to look at a 24"-specific DJ bike, but you can definitely ride 26" as well. If you want to see some MTB 26" street, Google Martin Soderstrom. He rides street, park and dirt.

One main difference is bike sizing. In BMX, anything over 21" top tube is considered a long frame, with 22" being weirdly long.

But, in MTB, because of the slanting of the top tube and room for bigger wheels etc., a Small is generally a 21.5"tt, Medium is 22" and Large is 22.5"tt. (That's measuring top tube the bmx way, meaning measuring the top tube from the center of the head tube to the center of the seat tube. Many DJ-specific frames are measured this way. But the mountain bike industry often uses other methods, like "effective top tube" measurement, or even just seat tube measurement--these are not very helpful for DJ bikes).

I'm 6'1" and I ride a 22.5"tt Black Market Mob. Guys my height do ride 22"tt bikes as well, but a 21.5"(Small) is most likely going to feel too small for you.

Unsecure image, only https images allowed: http://fcdn.mtbr.com/attachments/urban-dj-park/775231d1361767565-need-help-first-bmx-dj-bike-cockpitsize-blackmarketsoldier.jpg
"Effective top tube" measures a horizontal line out to where your seat would be if it was that high. This measurement is generally not used for Dirt Jumpers, although some companies do it, when their dirt jumper is just one mtb out of a big lineup of others.
Unsecure image, only https images allowed: http://surlybikes.com/blogimages/spew17_1.jpg
"Reach" is the best measurement, but it's more rare to see listed because it is harder to measure.
TRANSITION BIkes, however, does list it for their bikes: http://www.transitionbikes.com/2015/Home.cfm
photo
flag cmc4130
Posted: Jan 28, 2015 at 9:40 Quote
As between 24"-specific park/street mtb's versus 26", you'll find that the 24" scene is a lot smaller (at least in USA), but they do have some excellent bikes. When a frame is built around 24" wheels, it can have a shorter back end and the bottom bracket tends to be close to axle level or a little above it, rather than below axle level. This is very noticeable in bunnyhops and riding in skatepark transitions. Bikes like the Black Market Contraband 24", Mutant 24", Union Street Mollly Maguire 24", Tonic Fabrications Fall Guy 24", etc. At the same time, there are new school 26"-street/park frames that have ultra short back ends and higher bottom brackets (than typical dirt-oriented frames) which also are nimble for street. So, it comes down to a personal preference thing... you can't really say one is always better than the other.

For example: Bunnyhop Tailwhip MTB: www.youtube.com/watch?v=i0L_rs_meI4 People used to think they were impossible on an mtb... well not at all, now!

24"-wheel specific Union Street Molly Maguire. It comes with bmx-rear-hub spacing (110mm instead of 135mm spacing), 990 bmx u-brake mounts:
photo

A 24"-specifc DJ/park mtb does not necessarily have a shorter top tube. For example, these both have 22" top tube. So basically, we're not talking about a 24"-wheel "youth" mountain bike:
Unsecure image, only https images allowed: http://i255.photobucket.com/albums/hh138/upsetbmx/Specialized-P-Street-24---DK-Xenia-.jpg
24" mtb-park riding on a Union Street:
Unsecure image, only https images allowed: http://i255.photobucket.com/albums/hh138/upsetbmx/UNIONSTREET-img_0310tweaked_zpse1679ff9.jpg
flag travis-ridesbikes
Posted: Jan 28, 2015 at 9:56 Quote
cmc4130 wrote:
travis-ridesbikes wrote:
so ive been really bored with bmx recently just i feel like the bike is to small and would like something bigger i 270 ed my ride to school bike the other day(http://websta.me/p/893056637191991987_275567187) clip im quote proud of that 270 because well that bikes stand over is huge

Now to the real thing im 6 ft still growing 150 lbs ride a 21.25 tt in bmx with 8.75 rise bars ive got bar spins locked trucks all that fun stuff Smile . i will mostly be riding park, street with bmxers and occasionally dirt (not much in SD) im not really scared of big stuff i might very rarely do some very minor downhill on it. Mostly going to be tricks.

1. what size should i go i was thinking 26 but im not sure
im buying used so what things are important double wall rims and sealed hubs ae a given but what about forks and frame regarding material.(id like front suspension)
2.how much would a bike like this cost used of course
3.just pretty much give me a general description of stuff

thank you in advance



I also switched from BMX a while back. For riding park and street, you might want to look at a 24"-specific DJ bike, but you can definitely ride 26" as well. If you want to see some MTB 26" street, Google Martin Soderstrom. He rides street, park and dirt.

One main difference is bike sizing. In BMX, anything over 21" top tube is considered a long frame, with 22" being weirdly long.

But, in MTB, because of the slanting of the top tube and room for bigger wheels etc., a Small is generally a 21.5"tt, Medium is 22" and Large is 22.5"tt. (That's measuring top tube the bmx way, meaning measuring the top tube from the center of the head tube to the center of the seat tube. Many DJ-specific frames are measured this way. But the mountain bike industry often uses other methods, like "effective top tube" measurement, or even just seat tube measurement--these are not very helpful for DJ bikes).

I'm 6'1" and I ride a 22.5"tt Black Market Mob. Guys my height do ride 22"tt bikes as well, but a 21.5"(Small) is most likely going to feel too small for you.

Unsecure image, only https images allowed: http://fcdn.mtbr.com/attachments/urban-dj-park/775231d1361767565-need-help-first-bmx-dj-bike-cockpitsize-blackmarketsoldier.jpg
"Effective top tube" measures a horizontal line out to where your seat would be if it was that high. This measurement is generally not used for Dirt Jumpers, although some companies do it, when their dirt jumper is just one mtb out of a big lineup of others.
Unsecure image, only https images allowed: http://surlybikes.com/blogimages/spew17_1.jpg
"Reach" is the best measurement, but it's more rare to see listed because it is harder to measure.
TRANSITION BIkes, however, does list it for their bikes: http://www.transitionbikes.com/2015/Home.cfm
photo

that was very helpful ive rode my friends steel reserve and it was easy so i like 26 and they are far more common around me but what about aluminum vs cromo
flag cmc4130
Posted: Jan 28, 2015 at 10:06 Quote
travis-ridesbikes wrote:
that was very helpful ive rode my friends steel reserve and it was easy so i like 26 and they are far more common around me but what about aluminum vs cromo

If you're coming from bmx and riding street/park, I would say chromo. Aluminum is probably just as strong, but it's more of a cultural thing. Chromo steel DJ bikes tend to have the smaller-tubing bmx look.

The Steel Reserve is a quality bike.

Check out Black Market, TRANSITION, and NS Bikes . . . .
flag travis-ridesbikes
Posted: Jan 28, 2015 at 18:08 Quote
So aluminum vs cromo doesnt really matter and like what will a high quility bike have vs low
flag cmc4130
Posted: Jan 29, 2015 at 13:41 Quote
travis-ridesbikes wrote:
So aluminum vs cromo doesnt really matter and like what will a high quility bike have vs low

Right. A high quality bike could be either chromo or aluminum.

Check out the Black Market Edit 1. It would be considered a street/park type setup because of the higher bottom bracket relative to axles, and the frame being designed around a shorter rigid fork (or a short-travel suspension fork).

Unsecure image, only https images allowed: http://p.vitalmtb.com/photos/stories/2012/01/13/full_Edit1_American.jpg?1326469437
The main model prior to the Edit1 was the Mob. They used to be fabricated by S&M in California:
Unsecure image, only https images allowed: http://www.wired.com/images_blogs/photos/uncategorized/2008/09/25/tenbikes_092508_jmm_0214.jpgUnsecure image, only https images allowed: http://i729.photobucket.com/albums/ww294/billy_2626/blkmrkt55092.jpg
The 2015 TRANSITION BLT also has a higher bottom bracket than traditional DJ bikes. Notice how the bb is close to axle level or even slightly above:
Unsecure image, only https images allowed: http://www.sugarcayne.com/wp-content/uploads/2014/11/blt-transition-21-640x387.jpg
Compare that to the older TRANSITION Trail or Park (also a great bike). You can kind of see the chainstay sloping down and the bb being a little lower than axles. It's not a huge difference, but to some people it would matter.

photo
flag travis-ridesbikes
Posted: Jan 29, 2015 at 15:19 Quote
So like the lower bb is more for dirt because id think the center of gravity is lower and higher is better for park/street like just how i ride i land hard often so alot of fork travel would be nice and i do alot of drops fast and big not slow and tech so i think id like a lower bb with more fork travel
flag ricar
Posted: Jan 29, 2015 at 17:49 Quote
There is more to the cromo Alu decision than just picking one. What you ride may make you question Alu.

Is there a problem with steel?

Steel is heavy but there are newer processes that are making steel lighter but that can also make it behave a bit more like Alu. A steel race frame may last as long as three years (In the BMX world) before flexing out and needing to be replaced.

Is thee a problem with Alu?

An Alu race frame will last three months or less (in the BMX world) with many lasting less. Other than race frames Alu frames will be hugely over built

How can a race frame only last a couple months?

Alu has a bad tendency to work harden. Alu is quite stiff by nature but when you make it flex it gets even harder. If you keep flexing it you damage the "grains" or crystal structures that get tangled to give Alu the stiffness in the first place. What that means is that while the frame may not be cracked it will be weak and flex a lot, then crack.

How can Alu frames last years then?

They are hugely over built, to weigh as much or even more than steel frames. This prevents them from flexing at all and in turn prevents work hardening. This is why Alu frames tend to be unforgiving to vibrations and harsh landings, but they can last.

SnM Bike built ONE Alu frame years ago and it only lasted a couple minutes before the test rider brought it back in two pieces. Chris Moller then vowed to never build another Alu frame.

Alu also tends to tear where cro-mo tends to crack and at room temp will bend. Much safer when you nose case that 14' double. Alu also does not deal with grinds, it reacts poorly to abrasions and Alu tubes end to dent easier. You will rarely see an Alu frame destined for park or street riding. In the dirt however all bets are off tire pressures are less and the harshness can be lessened, add a sus fork and no longer even a thought. Now it becomes geometry more than anything else.

Can you ride park with an Alu frame?

Sure, just realize grinds have the potential to kill your frame in no time, think minutes if you are not careful and tubes may dent easily. After that, go for it.

------------------------------------------------

The Higher BBs were a response to grinding rails. I like low BBs personally but I don't do rails, nor have I had pegs on my bike in the last 15 years. So yes, lower BB lower CoG and also you can run lower bars, better control. If you don't do rails IMO go low BB. If you do like rails, higher BBs may be your better bet.
flag cmc4130
Posted: Jan 30, 2015 at 7:51 Quote
the most common aluminum DJ 26" choice seems to be the Specialized P.3:

photo

https://www.pinkbike.com/forum/listcomments/?threadid=114787&pagenum=40

dual-suspension dirt jumpers i.e. Slopestyle bikes also tend to be aluminum. Specialized P.Slope, Black Market Killswitch, Transition Double, etc.
http://www.specialized.com/us/en/bikes/bmxdirt-jump/pseries/pslope

P.Slope:
Unsecure image, only https images allowed: http://cdn.mos.bikeradar.com/images/news/2012/08/21/1345562638147-zwxs31bzhc8e-670-75.jpg
flag mserno75
Posted: Jan 30, 2015 at 8:43 Quote
I've always ridden BMX bikes and recently had a chance to ride a Trek 26 DJ at Rays. I really liked the way it rode over the jumps and like the feel of the suspension fork. I went out and bought a 2015 specialized P3 and love it. I've had a little time to hop some stuff on the street so far and really like the feel of it there too. It's definitely a different feel but I like it. I like the semi knobby tires so I can ride in some slippery weather and the disc brakes are great too. I'd say go for it. Just be ready for it to feel like a completely different bike. Don't try to make it a BMX bike
flag cmc4130
Posted: Jan 30, 2015 at 8:52 Quote
mserno75 wrote:
. . . . I'd say go for it. Just be ready for it to feel like a completely different bike. Don't try to make it a BMX bike

Yeah, I agree. I would say that in the first few days or week I had a DJ bike, it felt weird and I wasn't sure about it.

But, after that, I started hitting pretty much every trick I did in bmx, and I started loving it. The big wheels and sus fork make you feel like you can go bigger on everything, with less impact/consequence. Of course, you can go big on 20"s too, but I think the comfort level just pushes you to take your riding bigger. I hit bigger doubles in my mid-30's than I ever did before. I tried to convert my bmx friends--some went for it, others didn't want to try. Same with Downhill. One of my old bmx friends lived in Denver and rode bmx his whole life (did backflips, flairs, truckdrivers, etc.)...had never ridden DH before (even though he lives 2 hours from the mountains). I traveled up there from a state with no mountains and convinced him to try it; he was throwing suicide no-handers off big jumps the first day on the mountain and bought the rental bike on his first day riding DH. Now he has a 20", a 26" DJ, and a 26" DH bike. Cool
flag lalena
Posted: Jan 30, 2015 at 19:06 Quote
Since you mentioned you like street and park as a primary, I'm a huge fan of the steep and short angled frames such as the Transition BLT or the Deity Streetsweeper. There may be others out there that I'm not aware of, that I'm sure others here can point you to. Also, coming from a BMX you'll probably find the steeper shorter angles of these bikes more familiar.

If you go with a 26" bike, I would definitely go with a "Long" if you're given the choice.

Cheers and have fun! I bet you're gonna have great style on your new bike coming from BMX.
flag ricar
Posted: Jan 31, 2015 at 7:32 Quote
With 24" wheels and 170mm crank arms, 9.5 shoes, 24" between the front axle and the crank spindle will allow me to cross the bars and buzz my toes without knocking my foot off.
flag travis-ridesbikes
Posted: May 12, 2015 at 22:43 Quote
So I've finally started to really start looking theres only one 24 inch on cl in my areahttps://sandiego.craigslist.org/csd/bik/5014286657.html. Is this good or not and its cheap so if it needs some money put into it i can do that or this https://sandiego.craigslist.org/nsd/bik/4986069814.html theres a specialized p2 in my area also ive seen a couple in the buy sell on here that look nice im limited to around 600 bucks can that get me something good enough to not snap
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