[disasterarea]

I've done a search looking for stem length but couldn't find anything relevant. The 100mm stem on I have on my ht feels good for everythingelse but too long when doing downhill duty. The question is how short need I go? Should I shorten to least 50/60mm or more to make a real difference? Another problem is I probably won't be able to try the stem on my bike before buying i.e. the shop will not take the stem back if I've used it on my bike. Hence the seeking of advice here.
Also, should I be considering 31.8mm? Although I'm only 155lb and don't really think I'll test the bars to destruction, this new sizing will probably take over the old so I was just worrying about handlebar availabilty few years down the road. Thanks

 

[lovebunny]

ive allways used a 50mm zero rise stem on my bikes. i use a thompson elite.

 

[lovebunny]

oh and i just use the standard size. not 31.8

 

[disasterarea]

Wow, that was quick. Would a rise make any difference in handling? Tnanks.

[/QUOTE=lovebunny]ive allways used a 50mm zero rise stem on my bikes. i use a thompson elite.[/QUOTE]

oh and i just use the standard size. not 31.8

 

[Spunger]

Yes length and rise make a difference. Here's what I've found pro/con wise of switching.

Pro's of a short stem would be..........you are closer to the head tube meaning your steering is more spot on. Plus in the DH world it allows you to get a better stance on a DH run. A con would be that your closer to the bars, maybe even so close it's uncomfortable.

A longer stem slows down the steering. Helps on climbs as well. You don't see many DH rigs with anything longer than a 70mm stem and can go as short as 0mm length.

If you get 31.8 stem you gotta get a 31.8 bar (more $$$) or spacers to run regular thickness bars. Not a big deal though.

Rise..........eh on DH you see anything from 0 degree to 10 degree. That is about where you want to be. Any higher than that and it starts effecting the steering geometry. For example back in the day I probably did the same thing you would do with no info, just randomly bought a stem. Well it turns out the stem was like super short but had like 30 degrees of rise. It rocked on climbing but was funny for everything else. It was back in the KORE days

You can get plenty of bars in either size so don't worry, it won't change that quick on ya. My DH bike is setup with the integrated stem set at 55mm. It's about where I'd want it. Any longer or shorter would cramp me. Just sit on your bike and get a feel for what you have now, and figure out. I started off on my FR bike with a Raceface Diablous 70mm. Rocked for DH and jumping. I switched to a 100mm stem with a 15 degree rise and it's more where I need it (for climbing and all around riding instead of JUST DH and jumping). If the bike with a 100mm feels long I'd go with a 70mm. You wouldn't think a 50mm and 70mm is that much difference (it really isn't) but once you mount bars it's a difference.

SO.......after all my rambling.........70mm should do it. A GOOD shop will set you up with the right stuff in the first try. It never hurts to ask.

 

[banj]

I like to keep the stem on my hardtail between 60 and 70mm because I use it for everything. You should be happy with something in that range because it won't be too short or too long. See if you can borrow a stem off of a buddy if you're really worried.

 

[buildyourown]

Are you trying to set this bike up for DH only, or as an all arounder? Personally, I run a 70mm on my DH bike cause I like a roomy top tube. The slower steering never seems to be a problem. Stem rise can be duplicated with spacers, though some snobs think spacers are tacky. This is controlled by your height. If your legs are longer, you back will be more hunched over the bars when standing, hence you will need a taller stem.

If I were trying to build a bike that could do it all, I don't think I would go shorter than 100mm. (IMO)

Most decent shops have a box of stems that you can try before you spend good money. The shop I worked at, had all the stems in bags so we could install them and still sell them for new.
If your shop can't help you out, you could probably find a cheap one used for $5.

 

[Bikael Molton]

I like my 70mm Thomson for trail riding. It's short enough to not be twitchy and too far over the front for descents, but still long enough for climbing... but it all depends on your body, your bike and what you ride. 70mm could be a good starting point. buy a really cheap one and see if it works.

-rob

 

[MMcG]

I like my 70mm Thomson for trail riding. It's short enough to not be twitchy and too far over the front for descents, but still long enough for climbing... but it all depends on your body, your bike and what you ride. 70mm could be a good starting point. buy a really cheap one and see if it works.

-rob

I just put a 70 mm on my Hollowpoint - from a 90mm that was on it previously and so far I'm liking it. Steering feels better and so far it hasn't hampered me when I had to pedal uphill. The bike has a long top tube and the 70mm seems to have put the cockpit at the right length for me now. This is my aggressive trail bike so it should work well I think.

 

[buildyourown]

I think peoples personal preference may stem from their height. (no pun intended)
Think of it as scalable. I'm 6'1" so I run a 70mm on my DH. Somebody who is 5'9" might get the same feel out of a 50mm.

 

[MikeD]

It's really hard to know what to tell you without knowing how tall you are, how long your top tube is, and how tall your bars are already, so bear in mind we're all speculating here.

I think a 70mm is probably a good guess...that's the longest stem I like for Dh stuff (although I personally like 60-70mm best of all, just to keep some more weight on the front end compared to a 40-50mm) and also the shortest I'd use for trail/XC riding. 70mm should feel significantly shorter than 100mm without neccessarily cramping your position.

Might try a layback post at the same time; this way, when you sit down on the bike (non-DH riding), the body position won't be all too different from what you're used to. Weight bias will change, though, making climbing harder. But, when you stand up (DH riding), the front end will be shorter and the seat will be further back and more out of your way.

As to rise, on a short stem, rise is fairly insignificant, so there's just not that much difference between 10 and 0 degree stems. The 10 deg will allow you to flip it over to raise or lower a tad without changing spacers or anything. Could be an issue depending on how much steer tube you have. Lower front ends corner better, but are more intimidating when it gets steep and sketchy. (not less capable, mind you, but just more psychologically intimidating...)

Pretty odd that a shop won't let you put the stem on and ride it around the parking lot before buying. I'd try a new shop...

You could also look at something like the ad-vice stem from Easton, which is adjustable.

Oversize or normal bars...hmmm...don't mind oversized bars, myself, but don't notice any huge difference when riding them, either. Plus, answer and easton only make them in big high-rise bars....if only they did a low-rise version. I'd say if you're looking to get a new bar at this point, oversized is worth a look, if there's a 31.8 stem you like. (thomson X4...mmm) Otherwise, don't sweat it.

 

[Zutroy]

I think peoples personal preference may stem from their height. (no pun intended)
Think of it as scalable. I'm 6'1" so I run a 70mm on my DH. Somebody who is 5'9" might get the same feel out of a 50mm.

It's all personal pref...I have been riding with a 50mm, but this year I'm switching to 70mm with a shorter TT to try and move forward on the bike since i have really long arms and short legs. Do what feel most comfortable.

 

[disasterarea]

A big thank you for everyone’s advice.

MikeD, here’s some vitals. Framewise, it’s listed as 22.5” tt but I measured it as 21.5” from stc to htc, st is 16”. There’s a 1” riser with 1.5” stack below a 100mm stem bolted to a 100mm fork. I’m 5’9” and 29-30” inseem.

Buildyourown, you’re spot on with the all rounder comment, and funnily enough, I also went to a different shop from my first post, before reading yours and the chap there said that since it’s a ht I’ve got, a 90mm/5degree stem would be best to keep versitility. He said the 90mm would allow me to carry out XC/fr and DH duty. However, can 10mm be that much of a difference?

Since I am pretty green to this dh and dj business, maybe I should just suck it up to my lack of skill being the real problem. So before selling my 100mm stem plonking some readies for a new one, I’m off to the trail and see.

Thanks again to everyone.

 

[MikeD]

I'd still see if someone will let you slap a 70mm on, just to try it out...from your description, sounds like it'd be a good length. 80mm, perhaps, too, but I don't think the 90mm will change all THAT much, especially since you're looking to sort of change your style of usage, not just fine-tune your body position...

If you can find or buy online the Weyless/Supergo type stems, they're cheap and pretty good, but only come in 40, 60, and 80mm...I wish they had a 70...

 

[lovebunny]

if you want to get a 31.8 i think that race face sells the diabolus as a combo for 130