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Re: Trying not to waste more money on bike fits

Posted: Sat Jan 05, 2019 8:59 am
by robeambro
silvalis wrote:
Sat Jan 05, 2019 4:52 am
Can't find a picture right now (might take a pic of my own later) but essentially SMPs reach a width (picked an arbitrary number here) of 10cm a good 10-20mm back compared to other saddles. Meaning you sit further back on the saddle than you would on others. Meaning you push it forward to maintain the same seat position relative to the BB and often dont need a setback seatpost.

I think Steve hogg wrote a bit on it.
https://www.stevehoggbikefitting.com/bi ... bout-smps/

yeah. dot point 8.
A-ha. Thanks.

But now.. I’ve read online that the width where the “anatomical centre” of the saddle is, is at 7.2cm rather than the 10cm you describe.
Which one is correct?

Re: Trying not to waste more money on bike fits

Posted: Sat Jan 05, 2019 8:59 am
by Weenie

Re: Trying not to waste more money on bike fits

Posted: Sat Jan 05, 2019 9:40 am
by TobinHatesYou
I have gone through the biggest extremes with saddle rail positioning. I was using an ISM PN 3.0 for a while before switching to an SMP Glider. The ISM had to be slammed fully back while the SMP is almost slammed forward. My Romin Evo was almost centered in the rails. :p

Re: Trying not to waste more money on bike fits

Posted: Sat Jan 05, 2019 12:06 pm
by robeambro
TobinHatesYou wrote:
Sat Jan 05, 2019 9:40 am
I have gone through the biggest extremes with saddle rail positioning. I was using an ISM PN 3.0 for a while before switching to an SMP Glider. The ISM had to be slammed fully back while the SMP is almost slammed forward. My Romin Evo was almost centered in the rails. :p
I was actually considering using an ISM saddle - did you change it because it looked weird (although you switched to an SMP after all, so I dare say this was not the reason) or?

Re: Trying not to waste more money on bike fits

Posted: Sat Jan 05, 2019 6:40 pm
by TobinHatesYou
I switched because the ISM was not comfortable to ever sit up on during climbs or after long hours.

Re: Trying not to waste more money on bike fits

Posted: Sun Jan 06, 2019 1:23 am
by silvalis
robeambro wrote:
Sat Jan 05, 2019 8:59 am


A-ha. Thanks.

But now.. I’ve read online that the width where the “anatomical centre” of the saddle is, is at 7.2cm rather than the 10cm you describe.
Which one is correct?
I can't comment on that - I have no idea, but my knee jerk 2c worth is that setting "7.2cm" as an anatomical centre is absolute bs, especially considering everyones undercarriage is different. Otherwise there would be no need for saddles of differt widths, would there? If you have a computerised fit report, you could figure out where the software thinks your centre is, but the real take away is to just choose a number and stick with it, so it can be applied across all your bikes

SMPs and ISMs need quite a bit of commitment. I dare say you need someone to fit you (or at least someone to set it up properly the first time), then you need to sit with the saddle for months.
Otherwise I'd just get something easy to get along with. Like an aliante, romin evo or a fabric scoop.

Re: Trying not to waste more money on bike fits

Posted: Sun Jan 06, 2019 3:15 am
by TobinHatesYou
Oddly I think the Tri/TT oriented ISMs are better suited for general road riding than their PN line. The PNs simply aren’t designed to ever sit up on with your pelvis rolled back into a “normal” position. If you do try an ISM, I would suggest staring with a PL 1.0.

Re: Trying not to waste more money on bike fits

Posted: Sun Jan 06, 2019 10:12 am
by robeambro
Thanks guys! Judging by your feedback, I think I should resort to ISM and SMP only if I find myself dissatisfied with a more traditional shape :)

Re: Trying not to waste more money on bike fits

Posted: Sun Jan 06, 2019 11:18 pm
by robeambro
Ok so, I guess I will ask one more question.

As some of you may know from reading this, I've had two bike fits. The results are attached. (of which I trust more the second one).. (FYI, The second fit was achieved with an handlebar with 80mm reach and ideally 40cm wide, but I was ok with 38s as well. I have no idea what handlebar was used in the first fit, but I'd guess it had similar reach)
Given these fit resultsWould you guys think that I could fit well on a Venge 56 with a 100mm stem and 38cm wide handlebars?

My thoughts:

Stack:
I’d need from 1.5 to 2.5cm spacers, depending on what fitter I want to trust (I'm inclined to trust the second, but anyway, my back would probably get used to either). So not a tower of spacers but surely some will be required.

Reach:

Ideal reach is 381 W/ 110mm stem and 80mm handlebar reach
The Venge will be 398 W/ 100 stem and 75mm handlebar reach, minus some 2-4mm given from the spacers.
Basically I have 17mm excess frame reach which is then compensated with 10mm shorter stem, 5mm shorter handlebar reach, and 2/4mm which I recoup by having the spacers.

So yeah in theory it sounds feasible, but I wonder whether the short stem will make it too twitchy. Would it be a functional faux pas? Would I have a bike that's difficult to handle? Am I missing something?

I’m just torn between this and a more sensible R5, which would fit me a bit better. I just don’t love that bike, that’s all, and if I can sit on a Venge with no negative consequences (ie bad fit), then I’d really prefer that. I know it sounds childish and all, but I don't get any "wow" feeling when I look at other bikes..

Re: Trying not to waste more money on bike fits

Posted: Sun Jan 06, 2019 11:32 pm
by AJS914
The 56cm Venge comes standard with a 100mm stem. On average Specialized seems to be specing shorter than average stems so I wonder if they are built to handle best with those stems? Of course, it doesn't stop the pros from riding small frames and specing 13/14/15cm stems.

I'd find a Venge to test ride to get a bit of a feel for it.

Re: Trying not to waste more money on bike fits

Posted: Sun Jan 06, 2019 11:57 pm
by silvalis
10mm off the stock stem shouldn't change the handling significantly, i'm sure you'll compensate quickly. What AJS said. test ride. Maybe they can throw a 90mm stem on to test too.

Re: Trying not to waste more money on bike fits

Posted: Mon Jan 07, 2019 10:06 am
by robeambro
Thanks guys.
I wish I could test ride, but the only Specialized dealer anywhere near me is doing so badly that they do not seem to have any 2019 models in the shop. And in the Netherlands in general, people don't seem keen to give test rides, and I've checked with Specialized, doesn't seem to be any organised test day.

So just trying to check whether my calculations make sense and on paper I should fit..

Re: Trying not to waste more money on bike fits

Posted: Thu Mar 14, 2019 3:24 pm
by robeambro
Hi guys,

rather silly question. I hope somebody can clear this for me. I have ordered my new bike (yay!), and just want to figure out how many spacers (if any) I will require.

As you can see from my two bike fits above, I was suggested a stack of 581 (or 571, depending on which of the two one wants to trust). I don't really know how the jig used for the fit accounts for headset top caps.

Now, my bike of choice will have a stack of 565mm. To get to 571/581, I need 6/16mm. To get there, I assume I should include in the total the headset top cap, correct? This means that I would need pretty much little to no additional spacers (depending on the height of the headset)?

Re: Trying not to waste more money on bike fits

Posted: Thu Mar 14, 2019 4:48 pm
by zefs
You are correct about the headset height, yes.

Re: Trying not to waste more money on bike fits

Posted: Thu Mar 14, 2019 5:25 pm
by gurk700
This might be controversial but I'll go ahead and say,

1- You can easily learn bike fitting yourself. (Never had a bike fit. 5 years of hard training. 0 injuries. 0 discomforts.)
2- Your bike fit doesn't stay the same. (There is mechanics that won't change but some preferences will. I'm way more flexible than when I first started. This changes things)
3- A lot of bike fitters (not all) don't even know what they're doing. They look at numbers. We're not robots. We have a certain feel for things and might choose things that don't make sense from a purely lab-scientific point of view.

Re: Trying not to waste more money on bike fits

Posted: Thu Mar 14, 2019 5:38 pm
by robeambro
zefs wrote:
Thu Mar 14, 2019 4:48 pm
You are correct about the headset height, yes.
Thanks! Then it turns out I should be able to ride my new Tarmac without spacers. :mrgreen:
gurk700 wrote:
Thu Mar 14, 2019 5:25 pm
This might be controversial but I'll go ahead and say,

1- You can easily learn bike fitting yourself. (Never had a bike fit. 5 years of hard training. 0 injuries. 0 discomforts.)
2- Your bike fit doesn't stay the same. (There is mechanics that won't change but some preferences will. I'm way more flexible than when I first started. This changes things)
3- A lot of bike fitters (not all) don't even know what they're doing. They look at numbers. We're not robots. We have a certain feel for things and might choose things that don't make sense from a purely lab-scientific point of view.
Thanks for your input. I agree with most points. However, this was started some 5 months ago, so now it's all done :mrgreen:

Re: Trying not to waste more money on bike fits

Posted: Thu Mar 14, 2019 5:38 pm
by Weenie