# How does stem length and frame length affect handling



## Fargo1 (Oct 19, 2012)

I'm considering purchasing a new Goblin and I am struggling between small and medium frame sizes. So I am considering getting the larger frame and putting on a smaller stem. How does the handling of a bike change in regards to going from a 110 mm stem to a 75mm or smaller stem. Between these two sizes I should be able to get either frame to work. I just don't know if I am better off with a shorter frame and a longer stem or a longer frame and a shorter stem. The smaller frame is about 3/4 shorter in effective top tube as well as wheelbase length. I will be riding mostly single track trails. But I do really enjoy doing slow tight obstacles as well. Please provide some input as to the effects of wheelbase length, stem length, and even standover heights. This is driving me nuts Thanks.


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## Cayenne_Pepa (Dec 18, 2007)

Please provide us your height and inseam....


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## jeffj (Jan 13, 2004)

Look for something with shorter chainstays than the Goblin has (@ 450mm = 17.7") if you want good tight handling. That's getting to be on the long end of things for a playful handling hardtail these days.


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## Fargo1 (Oct 19, 2012)

jeffj said:


> Look for something with shorter chainstays than the Goblin has (@ 450mm = 17.7") if you want good tight handling. That's getting to be on the long end of things for a playful handling hardtail these days.


Thats good to know. I was looking at overall wheelbase, but never considered just the chainstays.


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## Fargo1 (Oct 19, 2012)

jeffj said:


> Look for something with shorter chainstays than the Goblin has (@ 450mm = 17.7") if you want good tight handling. That's getting to be on the long end of things for a playful handling hardtail these days.


I know this is common practice but, to be honest, I don't really see how looking at inseam helps with sizing the bike apart for stand over height. I am 5' 9 1/2"with a 33" inseam so standover is not an issue. But reach is. In regards to the Goblins, (and most other bikes) both the small and the medium have the same headtube length so their is no difference in head tube or handlebar height between the two. So once the seat is adjusted at the same height, the bikes will be exactly the same except for an additional inch of seat post showing and the distance between the seat and the handlebar is different. So in the end the only meaningful difference is the effective top tube, which will affect overall wheelbase length and the length of the required stem to find the appropriate reach. Which is what brings me to question whether its better to have a shorter bike with a slightly longer stem or a longer bike with a shorter stem. Am I missing something?


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## Fargo1 (Oct 19, 2012)

jeffj said:


> Look for something with shorter chainstays than the Goblin has (@ 450mm = 17.7") if you want good tight handling. That's getting to be on the long end of things for a playful handling hardtail these days.


I've been thinking about this comment. Is there something inherently better about a short chainstay, or is that just a good indicator the wheelbase will be short for a given bike size? Wouldn't the actual wheelbase be of more importance than the chainstay itself. It would seem to me seat angles and head angles would play as big of a role in total wheelbase as chainstay length. So I am asking if their is something better about a shorter chainstay or if its just a good way to shorten the wheelbase while maintaining other dimensions.


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## tooclosetosee (Aug 2, 2011)

I have a 17.5 HT and to get the proper comfortable reach I put a 120mm stem on the bike. This puts me very far forward and is very sketchy on sharp turns and descents. When I got my last bike I was between medium and large. The medium came with a 90mm stem and the large with a 105mm stem. I thought the medium with 90mm stem was too tight and I didn't want to have the same problem that I have with my HT and the long stem by putting on a long stem to be comfortable. So I went with the large and put on a 90mm stem. With 680mm bars it feels very natural. 

I don't know what the disadvantages are with running too short of a stem. I know it will speed up the steering, but if you compensate for a wider bar it shouldn't be a problem. I guess if you go too short of a stem for the style of bike it is and style of riding that you do then your weight will be too far back and you won't put enough weight on the front wheel for proper traction and climbing. 

Based on my limited knowledge it seems that for XC riding if a 90mm to 110mm stem doesn't work with you and your bike then the bike is not a good size for you. 

From my experience a shorter chainstay also helps with climbing as you have more weight over the back tire and it decreases slip. A bike with a longer chainstay means that you have to either stay in the saddle while climbing or have your weight farther back over the wheel to prevent slip. A shorter wheelbase also helps with quicker handling and getting around sharp turns.


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## AndrwSwitch (Nov 8, 2007)

I've had 65, 80, 90, and 100 mm stems on my current mountain bike. I have it at 90 mm right now. With the 65 mm and 80 mm stems, I found that it was a little harder than I liked to keep the front wheel planted, and climbing was a little awkward - the reach was shorter, I had to get more forward to keep the front wheel down, but the reach was shorter... lame. With the current stem, I'm pretty happy. I was happy enough with the 100 mm stem too for about a half hour - handling felt fine - but the reach was a bit long for me, and it made my back hurt.

I never tried to wheelie with the shorter stems, let alone work on wheelie drops and skills of that nature. Sometimes I wonder if it'd be easier. My experience with what I did do with the shorter stems suggests that it would.

So, OP, this is going to depend some on what you want from the bike. While current fashion in XC is trending to shorter stems too, it's paired with wider bars and riding position is a wash. The AM kids like really wide bars and really short stems and sit more upright than I want to. But they're doing something different than me, and I think we're both right.

I guess just going on your description of what you do, I'd be inclined toward the smaller bike and longer stem. But hopefully I've given a useful view here.


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## shibiwan (Sep 2, 2012)

I think I may be the odd one here....I'm 5'5" / 29 inseam and found that I'm most comfortable on a mid-large frame (18"-19") bike. I gravitate to a shorter stem (80-90mm) with a 20 degree rise or so. Also, a TT length of about 23" feels right for me and seems to be kindest on my 40-year-old back. I'm averaging 10-12 miles of singletrack mountain trails almost daily (includes riding to the mountains 2 miles each way) and any sign of poor fit shows up almost immediately.

The shorter stem does help in getting the nose up (especially on the Klein Mantra) but not to the point that the front wheel feels loose. I also found that going to a longer handlebar felt much better for control - I'm now using an Answer Protaper 720 AM Carbon riser bar and compared to the shorter (630mm) Bontrager bar I had, the bike feels more stable and yet remains responsive.

-S


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## Fargo1 (Oct 19, 2012)

Very good information guys. I think everything that was said makes sense. You've given me good stuff to think about in this decision. This is what I am looking for.


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## Mutantclover (Oct 1, 2006)

*Fork trail*

For me it has to do with fork trail. The greater the trail (ie the longer your fork or more slack the head angle, or shorter the fork rake), the shorter the stem that feels right. I think the scientific reason for this is because

1) when you turn the bars, the stem kind of "flops" downward as it moves to the side. The longer the stem, the more the "flop"
2) a bike with greater trail naturally wants to lean more for a given turn radius, this is why they are "more stable" feeling
3) at slow speeds, when you combine the bike wanting to lean more when you turn, and the long stem giving you more of a "flopping over" feeling, not to mention causing more of your weight to rest over the front of the bike, it doesn't feel right

As an end result, in terms of the stem lengths I have used on my bikes over the years... All had 100-115 mm of fork travel for reference. When I first went to a slightly slacker head angle on a 26er, (about 69.5 degrees instead of 71) I needed to go down from 100 mm stem to 90 and it felt alright except when descending a very steep hill. (I am 6'2" so generally have a slightly longer stem than the average joe). Then when I made the jump from 26 to 29 wheels, even though the head angle was back to a slightly more upright 70 degrees, the trail was greater, and I could not get the bike to feel right with the same stem length as before. It needed to be about 10 mm shorter, so 80 mm felt pretty good. And now my bikes feel better going down steep declines as a bonus, while maintaining the right feeling on climbs or flats as well.


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## Mutantclover (Oct 1, 2006)

You should note too that handlbar geometry has a lot to do with it too. Are the bars wide, or do they have a lot of sweep? Things to consider. A bar with 8 degrees of total sweep at 680 mm, vs one with 9 degrees backsweep and 3 degrees upsweep at 720 mm, moves the position of your hands on the bike a lot, probably more than a 10 mm shorter stem but I don't feel like doing the math right now.


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## Fargo1 (Oct 19, 2012)

Thanks Mutantclover. More good stuff to think about. I hadn't thought about the handlebar 'flop' as you call it. But I know what you mean. I also hadn't give that much consideration to the handlebar length or sweep and how they could affect things. All good things to think about. I will likely read through this thread a couple of times to figure out what I need and how it will affect things. 

Thanks to everyone. Please let me know if you think of anything more in regards to stems, handlebars or even chainstay length now that it was brought to my attention.


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