Fit question stretched out on the hoods

For discussions about bikes and equipment.
MikeF
Posts: 4339
Joined: 11 Nov 2012, 9:24am
Location: On the borders of the four South East Counties

Re: Fit question stretched out on the hoods

Post by MikeF »

For reference here are the details on Mark's link
18863_original_1.jpg
"It takes a genius to spot the obvious" - my old physics master.
I don't peddle bikes.
User avatar
NATURAL ANKLING
Posts: 13780
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: Fit question stretched out on the hoods

Post by NATURAL ANKLING »

Hi,
If I am following this -
Its only the stack -1 " and seat tube - 15 mm and head angle diference :?:

So bars are 1.1" lower 28 mm, seat is 15 mm closer (horizontal) to BB and bars, head angle slacker so wheel base is corrected to larger frame :?: And heavier steering offset by more forward body position :?:

Are you going to bother when you could just move the seat forward by 15 mm and then are you KOPS :?:
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.
Mark1978
Posts: 4912
Joined: 17 Jul 2012, 8:47am
Location: Chester-le-Street, County Durham

Re: Fit question stretched out on the hoods

Post by Mark1978 »

Chances are probably 95% that the frame will be repaired and this won't come up. But if there's a chance it could be replaced I'd then be starting from scratch, so to speak, so I could choose any size I wanted. So getting away from the short stem, minimal seatpost thing might be a refreshing change.
User avatar
NATURAL ANKLING
Posts: 13780
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: Fit question stretched out on the hoods

Post by NATURAL ANKLING »

Hi,
Mark1978 wrote:Chances are probably 95% that the frame will be repaired and this won't come up. But if there's a chance it could be replaced I'd then be starting from scratch, so to speak, so I could choose any size I wanted. So getting away from the short stem, minimal seatpost thing might be a refreshing change.

Yes aesthetically I can see that.............
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.
User avatar
NATURAL ANKLING
Posts: 13780
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: Fit question stretched out on the hoods

Post by NATURAL ANKLING »

Hi,
Mark1978 wrote:That picture is over a year old, and just so happens I didn't have any back issues on that ride!

This is a more recent one http://www.sportsunday.co.uk/en20140#photo from a few weeks ago where I did have issues. Unfortunately it's a front on shot and I've got 10 layers of clothes on so it's of limited use!

This is a picture of how my bike is currently set up - without me on it! Please excuse the poorly fitted mudguards!

Image

It is somewhat frustrating to know especially as this time of year I only get to go out once a week. Especially as you can only really change one thing at a time.

Above does'nt look that out of place, you should see my heap.
Attachments
Could do with a side view ?
Could do with a side view ?
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.
User avatar
531colin
Posts: 16083
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: Fit question stretched out on the hoods

Post by 531colin »

NATURAL ANKLING wrote:Hi,
If I am following this -
Its only the stack -1 " and seat tube - 15 mm and head angle diference :?:

So bars are 1.1" lower 28 mm, seat is 15 mm closer (horizontal) to BB and bars, head angle slacker so wheel base is corrected to larger frame :?: And heavier steering offset by more forward body position :?:

Are you going to bother when you could just move the seat forward by 15 mm and then are you KOPS :?:


Seat tube angle is only 0.5 deg different, so seat is only a few millimetres forward.
They say the head angle is 2 deg slacker, and wheelbase 2mm shorter, so the top tube could be 15mm shorter.....but then I have a problem with their quoted reach, so I'm not following it, either..... :wink:
User avatar
NATURAL ANKLING
Posts: 13780
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: Fit question stretched out on the hoods

Post by NATURAL ANKLING »

Hi,
531colin wrote:
NATURAL ANKLING wrote:Hi,
If I am following this -
Its only the stack -1 " and seat tube - 15 mm and head angle diference :?:

So bars are 1.1" lower 28 mm, seat is 15 mm closer (horizontal) to BB and bars, head angle slacker so wheel base is corrected to larger frame :?: And heavier steering offset by more forward body position :?:

Are you going to bother when you could just move the seat forward by 15 mm and then are you KOPS :?:


Seat tube angle is only 0.5 deg different, so seat is only a few millimetres forward.
They say the head angle is 2 deg slacker, and wheelbase 2mm shorter, so the top tube could be 15mm shorter.....but then I have a problem with their quoted reach, so I'm not following it, either..... :wink:

I am simply quoting the info posted as "C" they list as shorter by 15 mm, I see now that is virtual horizontal.
"K" reach is - 3mm from BB to head virtual, so BB to virtual seat tube top is 12 mm.

There may well be a typo in info I have not studied that well............
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.
User avatar
NATURAL ANKLING
Posts: 13780
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: Fit question stretched out on the hoods

Post by NATURAL ANKLING »

Hi,
Virtual TT's look ok.
Ignore the seat stay dims as I have modeled it different, not attatching the stay at seat corectly.
Standover heights are between the two in frame trangle.
Added offset and trail.
Tyres 700 x 23.

Done in a hurry so check the dims...............
XS49 (CORRECTED CHAIN STAY - OFFSET & TRAIL ADJUSTED)
XS49 (CORRECTED CHAIN STAY - OFFSET & TRAIL ADJUSTED)

S52 (CORRECTED CHAIN STAY - OFFSET & TRAIL ADJUSTED)
S52 (CORRECTED CHAIN STAY - OFFSET & TRAIL ADJUSTED)


Edited for chain stay correction.
Last edited by NATURAL ANKLING on 14 Dec 2014, 10:03pm, edited 1 time in total.
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.
User avatar
531colin
Posts: 16083
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: Fit question stretched out on the hoods

Post by 531colin »

49cm looks OK, offset of 44.39 is an acceptable error for the industry standard 45mm offset.
For the 53 you have calculated a 53mm offset, which I don't think is likely, its likely to be a 45mm offset and the figure for the reach is likely to be wrong.
....that would make the reach 379 + 8 = 387, or 11mm longer than the smaller bike
If you feel like it, you could pick another size, and see if a 45mm offset works for that.......

(73 deg head/53 offset is going to be lively verging on unstable. If they were going to the trouble to make a fork with a different offset to the industry standard 45mm, I'm sure they would use it on the smallest sizes with a shallow head angle, where it would help to give a short reach without toe overlap, but with good handling)
Mark1978
Posts: 4912
Joined: 17 Jul 2012, 8:47am
Location: Chester-le-Street, County Durham

Re: Fit question stretched out on the hoods

Post by Mark1978 »

wow, in depth :D Interesting stuff :D
Mark1978
Posts: 4912
Joined: 17 Jul 2012, 8:47am
Location: Chester-le-Street, County Durham

Re: Fit question stretched out on the hoods

Post by Mark1978 »

Found an image of the 49cm frame

49cm
Image

52cm (mine)
Image
User avatar
NATURAL ANKLING
Posts: 13780
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: Fit question stretched out on the hoods

Post by NATURAL ANKLING »

Hi,
531colin wrote:49cm looks OK, offset of 44.39 is an acceptable error for the industry standard 45mm offset.
For the 53 you have calculated a 53mm offset, which I don't think is likely, its likely to be a 45mm offset and the figure for the reach is likely to be wrong.
....that would make the reach 379 + 8 = 387, or 11mm longer than the smaller bike
If you feel like it, you could pick another size, and see if a 45mm offset works for that.......

(73 deg head/53 offset is going to be lively verging on unstable. If they were going to the trouble to make a fork with a different offset to the industry standard 45mm, I'm sure they would use it on the smallest sizes with a shallow head angle, where it would help to give a short reach without toe overlap, but with good handling)

OK I said model but actually its a virtual model, but I did not calculate anything, its constructed as if would be in real life.
So I might have made an error.....very possible, or some of the dims they have used are incorect as their picture is just that, a picture with dims.

My virtual model is Constructed on a £5 K plus sofware of industry standard.

Like I said I did in a hurry but the head angle is tighter at 73 on 52 model (71) so offset is bigger and trail smaller than the 49 model.
The head angle and the frame & wheel base dims drive that, remember that the wheel base is only 2mm diff and a different head angle reflects the diff in offset and trail.
Any dims in brackets are "Driven Dims" derived from the fixed other dimensions.
So offset and trail are driven (calculated by other fixed dimensioned geometry, taken from their chart.

Its simple to change anything on my models, I can model all the sizes later after tea & LIDL shopping & bike Work :)

Hears a clearer (I hope) pic on specs to help you check my model, please highlight anything of concern.
Attachments
2014-12-12_140359.jpg
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.
User avatar
531colin
Posts: 16083
Joined: 4 Dec 2009, 6:56pm
Location: North Yorkshire

Re: Fit question stretched out on the hoods

Post by 531colin »

The embarrassing thing is I have access to one of those programmes, but I'm too stupid to be able to operate it!
OK, so any dimensions which are in brackets are dimensions which the programme has derived from the information you input.
I would be interested in seeing what happens if you re-input the dimensions for the 53, specifying 45mm offset, and leaving it to work out the reach,, and also if you input the dimensions of any of the bigger bikes, I reckon the offset will work out at 45mm

(on the 52, with a 73 deg. head, an "industry standard" racing geometry calls for a 45mm offset. If you want similar handling characteristics with a 71 deg. head, you would need a big offset, say sixty-odd to get a similar trail. Most manufacturers don't bother, but leave the small bikes with a slack head angle and standard 45mm offset, giving slow steering.....as in this case. Putting a longer offset with a steeper head angle is going the wrong way, and will give very twitchy steering.)
macaroon
Posts: 23
Joined: 19 Jun 2013, 12:19am

Re: Fit question stretched out on the hoods

Post by macaroon »

The 49cm will be too small looking at that picture. Your spacer stack is already bordering on too tall, I wouldnt fancy running anymore spacers.

Regardless, I think your problem is how you're sitting on the bike, have you read my post on the previous page?
User avatar
NATURAL ANKLING
Posts: 13780
Joined: 24 Oct 2012, 10:43pm
Location: English Riviera

Re: Fit question stretched out on the hoods

Post by NATURAL ANKLING »

Hi,
Geometry for the other sizes, all TT's are to their spec.

Edited 14/12/14 L58 head tube erro corrected to 196, no other change to previous geometry.
Edited 14/12/14 chain stay correction - offset & trail adjusted.
XS47 (CHAINSTAY CORRECTED - OFFSET & TRAIL CORRECTED)
XS47 (CHAINSTAY CORRECTED - OFFSET & TRAIL CORRECTED)

M54 (CHAINSTAY CORRECTED - OFFSET & TRAIL CORRECTED)
M54 (CHAINSTAY CORRECTED - OFFSET & TRAIL CORRECTED)

L56 (CHAINSTAY CORRECTED - OFFSET & TRAIL CORRECTED)
L56 (CHAINSTAY CORRECTED - OFFSET & TRAIL CORRECTED)

XL58 (CHAINSTAY CORRECTED - OFFSET & TRAIL CORRECTED)
XL58 (CHAINSTAY CORRECTED - OFFSET & TRAIL CORRECTED)

XXL61 (CHAINSTAY CORRECTED - OFFSET & TRAIL CORRECTED)
XXL61 (CHAINSTAY CORRECTED - OFFSET & TRAIL CORRECTED)
Last edited by NATURAL ANKLING on 14 Dec 2014, 10:13pm, edited 2 times in total.
NA Thinks Just End 2 End Return + Bivvy - Some day Soon I hope
You'll Still Find Me At The Top Of A Hill
Please forgive the poor Grammar I blame it on my mobile and phat thinkers.
Post Reply