Riding position alteration/question

[Epoch]

I'm looking to change the stem on my 97 Explosif to improve the comfort of my riding position a bit.

Current stem is 120mm with no rise, my dilemma is i'm currently thinking of a 100mm with either 5 or 15 degree rise.

I thought today the best way to ask this question was to get the following shots so people could see the current situation

(lesson for today is should have breathed in when having picture taken side onwards lol)

I think the rest of the set up is OK (seat height, fore/aft, angle etc), feels alright riding but i think I could just do with some more arm bend

 

[urbanfireblade]

Well if you ask me, your saddle should be set higher as your not maximising your power when pedalling- set it so your leg is almost straight when the flat part of your foot is over the pedal axis pivot point.

You'll find afterwards your leg is then only slightly bent when outstretched with your foot properly over the pedal axis, but not dead straight.You don't want it locking out straight.
Also i'd say you need either a larger frame or longer stem? maybe +10-15mm?

Just my opinion tho,

 

[Tad]

To set the saddle height I use the old method of pedal at the bottom of the stroke and heel on the pedal your leg should be straight so that when you clip in to the pedal (still at the bottom of the stroke) there is a small bit of bend in your knee.

 

[Splatter Paint]

I don't think there are any real rules regarding this. Recently I built a bike up that would give my shoulder an easier time. I've had surgery so I thought an nice upright riding position would help. I fitted risers and for short rides it was ok, on longer rides (1 hour +) I had a lot of pain in my shoulder blades. As an experiment I swapped the 2" risers out for flat bars - voila no shoulder pain. Yesterday I rode 2 3/4 hours no problem and my shoulder feels fine today.

I think just experimenting with stem lenghts and bars makes makes the most sense. Also, try shifting the saddle fore and aft, this can make quite a difference.

SP

 

[REKIBorter]

Correct stem length is a different thing to the right stem for you. To get the correct stem length sit as you are in the pictures with arms slightly bent at the elbows. Keeping your head still look down at the front wheel qr. The handlebar should be hiding the front wheel axle. If it in the middle you have the correct stem length. How much rise you have is a more personal choice and depends more on the frame/fork and riding style.

 

[Pickle]

I think your saddle height needs to go up a little bit more before deciding on stem length.

 

[SeeingisBelievingGTMuseum]

Current stem is 120mm with no rise, my dilemma is i'm currently thinking of a 100mm with either 5 or 15 degree rise.

I too think you saddle maybe just a tad low. Last year I did exactly what you have typed above and I've been loving it ever since.

 

[The_Grouch]

How tall are you? I too think the bike looks small and you could do with more reach not less!

 

[Anthony]

You shouldn't ever set the stem length primarily to achieve best fit. The stem length has a major impact on the steering geometry, i.e., the fundamental handling qualities of the bike. You have a longer fork than the frame was designed for, so you need a shorter stem. But if you feel your arms are stretched, then it may be that a shorter/higher stem would also help your posture.

If you look at the catalogue photo for the following year's Explosif, you will see that they had already gone over to a 105mm/15 degree stem as they worked out how to get the best out of suspension geometry. The frame geometry was exactly the same as in 97, they just changed the stems to suit the forks. As I say, that was mainly to keep the handling lively, but it also improves the riding posture.

Compared to a 120/0, a 105/15 would make the bars almost exactly an inch higher and an inch nearer the saddle horizontally. I'm not sure whether that would induce bent arms, or simply that the triangle made up of your back, your arms and the line from the saddle to the bars would just tilt upwards and backwards, i.e., your shoulders/weight would shift backwards. That is obviously a more dynamic position, in terms of ability to shift your weight about, but not so fast for head-down hammering.

I actually have four of those 98 stems at the moment and don't need them all, so I could send you one to experiment with for a small consideration.

 

[Anthony]

How tall are you? I too think the bike looks small and you could do with more reach not less!

The frame is a size 20, intended for height up to 6-6.