Thorn Cycles Forum
Community => Thorn General => Topic started by: janeh on October 18, 2012, 02:39:33 PM
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Hello,
My Sherpa has chipped paint and is going back for re spraying. I am thinking of swapping for a frame for straight bars. Thorn have recommended a 500L (I am 5'4" with standover 77.5cm). This has a top tube that is longer than that on my husband's bike (he is 5'10"). Does this mean Thorn are recommending a bike too big for me or is my husband's bike too small?!
Is their sizing advice generally good? It is difficult trying to size a bike when you can't see it but Thorn seem confident they can do it. The problem is though, once the components are swapped, the new bike is now 2nd hand.
The current frame has drops and is probably a bit too short (probably more due to me pushing for a short frame than due to Thorn's advice). I don't want to make a mistake again but I probably really should trust Thorn's advice. Obviously my husband's Marin Novato and a Sherpa have different geometry.
Any thoughts?
Jane
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Hi Jane,
For what it's worth and hoping it will help...
When I ordered my Sherpa, I didn't start from scratch on the sizing. At that time (Summer 2011), Thorn had a different sizing system, and I simply transferred my measurements from a bike (several, actually) that fit me perfectly. The Sherpa I received (a 560S with drop handlebars) fit just like my other bikes. The only "adjustment" from Thorn's usual was the inclusion of a large-layback seatpost to get my relationship with the bottom bracket to match my other bikes.
The Nomad sent in replacement was modeled after my Sherpa's measurements. It not as ideal a fit frame-wise with drop 'bars due to different geometry (590M with longer top tube than the 560S Sherpa's), but with some juggling of the stem's reach (shorter) and brake lever placement on the handlebars (higher and closer), the effective fit is the same as the Sherpa and matches my other bikes so it feels the same when on it. The Nomad also required the large-layback seatpost to put me where I needed to be over the BB with my preferred Brooks B.17 saddle, which has short rails; the seatpost setback makes up for that.
I do know the Sherpa Mk3 line was redesigned after my Mk2 was produced, and the new frame geometry would have resulted in a less-ideal basic fit for me. I do think it could have been adapted with adjustments in stem length (reach).
All of this is by way of saying I found Thorn's sizing to be excellent in duplicating the fit of a bike I already owned and liked and fit me properly. I don't know how it would have been if I had started from scratch.
Thorn have recommended a 500L (I am 5'4" with standover 77.5cm). This has a top tube that is longer than that on my husband's bike (he is 5'10"). Does this mean Thorn are recommending a bike too big for me or is my husband's bike too small?!...Obviously my husband's Marin Novato and a Sherpa have different geometry.
Without seeing the bikes or knowing if one or both have dropped or straight handlebars, I would guess the difference is due to geometry and intended use and preferred position.
Jane...do you have the opportunity to try some friends' bikes or perhaps take a test ride of a local bike so you can get an idea how a different frame/bike might feel or fit? Actually getting on a bike can make a tremendous difference, and even a cm one way or another on handlebar reach or height can transform a bike from good to bad or vice versa.
I hope something in this helps.
Best,
Dan.
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Hi Jane!
My S/O is the same as yours, but I'm a 1/2" to an 1" taller. Last year when I bought my Raven Tour, Thorn recommended I get a 487L, since I wanted to use the comfort bars. I've compared the specs on the old and new RTs, which Thorn says has the same geometry as the Sherpa, and the Virtual TTs are the same between the old (487L) and new (500L) RTs. I don't feel stretched out on the bike at all. Actually I've just bought a longer stem, and I often use the Ergon 5's to stretch out more.
The biggest issue for me though, was getting used to the comfort bars when I'd always ridden drops. The measurements didn't transfer well from my old bike style to the new, and it was VERY important for me to get the uncut fork to work the fit out.
So I would trust Thorn's recommendation, and enjoy the view! Actually, I hope to hear what you think about the handling of the new frames. ;D
Regards,
Holly
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Hello,
Think things have been clarified a bit more by taking a pic of me on husband's bike and sending it to Andy B. He confirmed what my thoughts were: That the bike was a bit too strecthed out but better position wise than my old bike (which was too small). So he still feels that the 500L will give me the position I need.
Thanks for the helpful comments,
Jane
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Jane,
I just built up a Sherpa using a 500S frame and it fits me perfectly, and I am the same size as you, I went for a small as I have always had problems finding a bike to fit me. I went for a small based on Andy's advice at the bike show at the NEC, I sat on a 500L and it felt too long for me.
But I feel you are always better taking a test ride before making the investment. Is it possible for you to visit thorn and have a go on a 500S or L.
Peter
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Hmm, is a bit difficult to visit SJSC. Need a 500L or S owner near Edinburgh!
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Hello Peter,
Do you have the same height and standover as me?
Jane
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For what it's worth...I cycle a 525L XTC with a standover of 77 CM and a a virtual top tube CTC of 55.5 CM.
I am 5 5 and have longish arms/legs but a short upper body. The bike is setup with drop bars. In order for this to work I needed to put on a short stem (8 cm reach) and need to put the saddle all the way forward.
On my straight/moustache bar bikes a virtual top tube of 54 cm is perfect for me without having to put the saddle forwards.
It looks like that 500S Sherpa has exactly that top tube length (540) so yes with straight bars it should be fine I would say :) The 500L is 575 I think that might be too big...
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Hope this helps Jane ... I have a Thorn Raven Tour 2009 model 512L (I have Thorn Comfort bars on it). My inside leg (shoes off, book between the leg, and measuring from the floor up) is 79cm. My height is 173cm. The Raven Tour top tube mid-point is about 75cm above the ground.
Yes, we are a long way from Thorn HQ! I am South of Edinburgh - you are very welcome to contact me and come and try the bike if you need to.
Richard
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Jane,
Sorry for the delay I am 162cm tall and my standover is 76cm. I have comfort bars set so the top of the bars are level with my saddle, but this is a personal choice. But I feel very comfey on my 500s. I am sure that I could have made a 500l fit but my biggest problem for every bike I have ever brought is reach, so the s was recommended by andy. Hope this helps a little.
Peter
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Thanks for the replys. I think the Thorn Raven just South of Edinburgh (and probably quite near me as we are in Penicuik) would be too big but thanks for the offer of a test ride.
Andy B was so sure I would be ok on the 500L that I went for this frame. Hmm, it's a long bike and I am actually not really sure it's ok. The 100mm 17 degree stem he suggested is too long I think and so far I am just using the 90mm one I already had. He suggests I raise the bars to get the right reach too. I'll just have to do more test riding, but if it doesn't feel ok I might be in a bit of a pickle!
Cheers,
Jane
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Jane
Glad you have got your bike. I am sure it will be fine. If it is any consolation, when I got mine I thought it was the wrong size.
I made small individual adjustments in this order:
1: Saddle height - extended to max height where I could only just reach the ground with the tips of my toes while seated (test ride and reduce by small amounts between tests so my hips are not moving up and down while peddling).
2: Handlebar height on the stem - so I could practically take pressure off my hands and not feel like I was falling forward.
3: Adjusted saddle forward and back so I did not slide forward or back while cycling.
Its amazing how even a small change of a few mm can make a difference.It took me a while but I am now totally satisfied with the fitting and comfort.
Keep us posted on your testing and final solution! At least with a Thorn you have 100 days to be happy with the bike!
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Even though it is just a frame you have bought and Thorn don't specifically offer the 100 days deal on Sherpa frames (I think), I'm sure they will offer to swap the frame for you if you ask them.
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From the Sherpa brochure:
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Hi All!
Perhaps the following will be helpful...
The Thorn FAQ, "What if I don't like my bike?" ( http://www.thorncycles.co.uk/FAQ/100day.pdf ) refers to "...all complete bike sales".
The Thorn FAQ, "What if there is a problem with my new bike?" is here: http://www.thorncycles.co.uk/FAQ/problem.pdf
Root link for the Thorn Cycles FAQ is here:
http://www.thorncycles.co.uk/faq.html
From the Owner's Manual ( http://www.thorncycles.co.uk/thornpdf/ThornBikeOwnerManual2Web.pdf ): "Thorn branded frames, framesets and frame kits are not included in the 14 or 100 day 'money back if not delighted guarantee'". [page 40]. According to this, the Thorn-branded bicycles are covered by a 14-day trial; the Raven (Rohloff) bicycles have a 100-day trial; both trials are subject to residency requirements and may not apply in some geographic areas, as noted in the brochures.
According to the Owner's Manual (ref. above), the warranty against failure or defects varies by model and/or intended use (i.e. competitive use and racing). All warranties apply only to new frames or new complete bikes (not used) and are valid only for the original owner.
That said, Thorn are very cooperative and committed to making things right for new owners and are easy to talk to if contacted directly.
Best,
Dan.
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Hi Jane!
Thinking more about your sizing dilemma...
Would it be possible to temporarily fit a much shorter stem than you presently have in order to simulate the shorter frame?
I'm thinking this might be an inexpensive approach to check and see if the shorter frame would work better for you.
Hoping for a good outcome for you.
Best,
Dan.
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Hello,
You are right I really need to thrash the issue out using different sized stems. Thorn cycles would probably (hopefully!) try to sort things out for me if there definitely is a problem but I would need to work out first if it really is wrong. The next size down is 35mm shorter so if I had this I could end up needing a long stem. Also I don't like the bars too low and when you raise them it does bring them closer.
It's a bad time of the year for a new bike! The dark nights, the cold..
Oh, and in addition, I forgot to mention; it's a lovely looking bike!
Best wishes,
Jane
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Jane,
I am glad you are getting the sizing sorted out, as said earlier in this chain; a few mm here and there can make all the difference.
A shorter stem most likely would fix your problem. Do you use flat handle bars, if you do then the thorn comfort bars give a very nice rear sweep which puts your hand position further back relative to straight bars. I think the sweep is 18deg.
All the best.
Peter
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Hello folks,
Here is what happened. I decided after testing that the bike is indeed too big. Asked Robin Thorn if I can swap it for a smaller one. He said yes but I have to pay £50 incl postage.
Quite reasonable except for the problem that there are no 500S frames in stock and only a 485L in black (my frame is red) and what's more, new frames could be 4 MONTHS before they arrive.
Oh dear this is not ideal. 4 months without a bike? Or a black frame I am not completely happy with. Happy days!
Jane
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Have you asked if you can keep hold of the frame until the one of te right size and colour comes into stock. I dont think that would be an unreasonable request and atleastit would keep you riding?
Andy
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Oh, Jane...
I am so sorry the frame did not work out for you; what a disappointment. Well, better to find out now, I guess, and have the possibility for return, but...
What rotten luck by circumstance to find the reds are gone! Oh, dear.
I was wondering how you were coming along with the trial, and hoping for the best, but it seems it was not to be.
Hoping some near-term resolution might yet be possible with an earlier-than-expected resupply of red frames.... Thanks so much for the update.
All the best,
Dan.
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Hello,
Yes I am allowed to keep the bike at the moment. I put on a 60mm 6 degree stem to make the same length as a 500S with 17 degree 100mm stem.
Robin now says that if the 60mm stem is ok then I should stick with that and not change the bike. It looks a bit funny though. But I am told looks don't matter. What does stem length do to bike handling anyway?
There's also the added complication of whether 475M would actually be better (bit longer than 500s but not as tall). Perhaps I should have gone through this before getting the bike but I couldn't get much further than "the 500L will be perfect for you".
Bye
Jane
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I find a longer top tube and therefore a longer wheelbase makes the bike more stable but feel less sporty. There is a risk that a shorter stem can make the steering twitchy but if you are not experiencing this then that is not an issue. Getting the right size of frame is a very subjective thing and only the right size frame will "feel" right for you. I ride a 535L with drops where Thorn would reccomend a 560S.
Not that it is going to help much but it is a case of trial and error in what feels right for you
Andy
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Hi Jane!
If it helps as another data point, most of my bikes are sized and setup in such way that I use stems with 80mm of forward reach. All allow me to have my preferred 45° back angle with slightly bent elbows when riding with my hands atop the brake hoods with drop 'bars, and the 'bar tops are even in height with the saddle top. I am now running a 60mm inverted uplift stem on my 590M Nomad Mk2. Why? The shortest top tube is the "Medium", a bit long for drop 'bars without adjustments, so....
With the short stem, compact reach/drop handlebars, and the brake levers placed so the blade ends are level with the bottom of the flat portion of the drops, I am in the same position as before (deep anatomic drops, 90mm stem, and brake levers set very high on the 'bars) and the bike feels the same 'cos my hands are in the same place as before, even though the stem itself is shorter. It matches the position I have on my other bikes.
In general, if everything else remains the same, a shorter stem with a longer top tube means more of the rider's mass is kept within the wheelbase of the bike, so the front wheel has a bit less weighting. Andy is right; the bike will feel more stable with less-sporty/twitchy handling. Also, because of the longer front-center (distance between BB and front wheel and head tube due to the longer top tube), the bike will be less stiff (mostly laterally, but vertically to a degree) due to longer tube spans. Overall, the ride should be workable.
As for steering leverage, that is best measured as a vector between hand position on the 'bars and the steerer's axis at hand level -- that is the effective moment-arm, regardless of stem length or 'bar type. This usually causes a flurry of protest among those who first hear it, but one can't argue with physics regarding leverage. Ah, but comfort and the need to accommodate individual physiognomy are different matters, and that's where handlebar width and hand orientation are a matter of individual preference. Same for reach to the 'bars, 'bar height, and back angle.
To that end, I have even had success fitting a 50mm negative stem (short stem, reversed so it extended rearward) with exceptionally wide drops for a barrel-chested, short-armed individual who very much wanted drops but found their forward throw exceeded his reach when he finally found the desired width. It all worked beautifully in the end and handling was unaffected because his final position was where it would have been had be been able to find short-reach 'bars in his required width. His leverage remained the same as well, and the bike didn't know the difference in terms of handling. The only quirk was the 'bars rotated 'round in an odd path at full lock when the bike was parked, but it was never a problem in practice.
Jane, I spent a lot of time with my Nomad setup to get things right in 3-D space along X, Y, and Z axes. You're absolutely correct; the 'bars move rearward as they rise. I was fortunate in already knowing how far rearward I need the saddle in relation to the BB, and I wanted the 'bar-tops at the same height as my saddle. Once the 'bars were in that plane, then it was a matter of mix-matching components till I got my hands in the preferred place ("reach") to give my back the 45° angle with slightly bent elbows I also wanted when riding the brake hoods with drop handlebars.
The articles at the following links might prove helpful honing in on what you want in terms of fit, either with adjustments to the present frame or in swapping to another size:
Choosing a frame size*: http://www.rivbike.com/kb_results.asp?ID=41
Fit, sizing, position: http://www.rivbike.com/kb_results.asp?ID=38
Common setup mistakes: http://www.rivbike.com/kb_results.asp?ID=40
Lesson in positioning: http://lovelybike.blogspot.com/2011/06/back-and-forth-lessons-in-positioning.html
The top tube ruse: www.rivbike.com/v/vspfiles/assets/images/ttr_excerpt.pdf
Determining correct size for touring bike: http://biketouringnews.com/what-size-touring-bike/right-size-touring-bike/
Finally, if you or others are considering drop handlebars, the following article is a useful read; it compares the myriad available bends and resultant reaches: http://ruedatropical.com/2009/03/road-drop-bar-geometry/
*Keep in mind (wrt the Rivendell links), Grant Petersen doesn't mind toe clip-front wheel overlap. I do. Andy Blance also avoids it by design.
Jane, I feel your understandable frustration and angst and am hoping something in the above might prove helpful to you achieving a good fit, either with this frame or the next.
Best,
Dan. (...who thinks "Fit-ness" would be a good term for bike sizing)
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Thanks for the comments,
Dan, I am quite embarassed by my angst!
I think some of my confusion comes from the difference between what Andy B said would be perfect for me (500L 100mm stem flipped horizontal) and what actually feels comfortable (quite a bit shorter). So my feeling was if the difference is that much, it must be the wrong size, but I take on board the idea that actually perhaps it's fine.
Perhaps I would have been better going to Thorn HQ but never mind.
Best wishes,
Jane
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Well, here's what happened. I now have a Thorn Sherpa size 475M in Black. I didn't want black initially but I like it. This frame size is described in the brochure as "very small", although to me it's not that small.
However officially the brochure says it's too small for a person of my height (5 ft 3" or 1603mm).
The horizontal top tube is 55cm and the seat tube angle is a degree more than the 500L. The standover height is lower than the 500L (this suits me well actually). All in all it feels better than the 500L. I haven't had time to to do that much practice on it so these are just first impressions. Who knows if the other frame was too big or perhaps I just like bikes that are too small!
It's been quite an expensive mistake actually so I woudn't recommend it!
Jane
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Hi Jane!
Thanks so much for the followup; I was hoping the story would have a happy ending for you. <nods> Yes, I love my matte black Nomad as I did the same color on my Sherpa. I'd never owned a black bike before and would never have thought to choose one previously, but having made the choice, now love it!
The main thing is to at last have the fit that suits you.
Best,
Dan.
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Hi Jane good to hear you found something! :)
A 55 top tube is for a road bike for somebody 5"5' too long, and for a straight bar bike OK generally.
So I doubt it's too small...women bikes need shorter top tubes on average....
I believe the 500L was 58 and I already wondered if that was a bit long...as I am 5"5' on the 58 TT Bianchi flat-bar mountainbike the manfriend has I am stretched like mad...
(Thorn...you may have to look into shorter TT lengths for women, it's a common sizing issue for women apparently :)
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Hello,
I have never been able to believe the different sizes of frames that I have been told are my size. Andy Blance has fixed views and it shows unfortunately!
I have spoken with someone else at St Joh St Cycles and gradually over a number of years found my size myself. Everyone is different. I have a larger sized bike than Jane but it still had to be worked out by myself. I have two Thorn bikes and have over many years owned a number of Thorn bikes.
The only way is to work it out yourself for yourself.
I have been to the shop many times but never felt the size offered was correct. I proved myself which size was my size.
It is a tough World and choice of bike ie personal. Make certain from previous bike ownership which size looks correct.
As shown previously Robin and his business will bend over backwards to accomodate errors. Thorn usually are willing to exchange even though there may be a fair cost for this.
John
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My sizing experiences...
You can fiddle about with:
Hi-rise stems (mountainbike stems)
Shorter stem/longer stem (8-10cm both very workeable)
Putting saddle forwards (if you have to, you have to)
As long as the standover is correct of course. A size up/down providing standover is correct can work.
My 525L XTC is actually too long. But I got it to work with 8 cm mountainbike stem and saddle all the way forward. That was it's comfy, but really the TT is 3.5 cm too long.
(not Thorns fault I got it off e-bay from a bikeshop and guy only measure seat tube not TT...well I don't want to ever sell it ATM so good he made a mistake)
If the top tube really is too long, you are banjaxed.
A really sneaky way to test TT length to go a bikeshop and try some mountainbikes if you are want straight bars and road bikes if you want drops ;)
Or, measure the reach on your other bikes from top of saddle where it inserts into seatpost to where you place your hands. Assuming position on bike you want to get is the same, you then have a reach to work with, I'd err on the side of 2 cm too short rather than too large.
As it's easy to get a 10cm stem VS an 8. But going from 8 to 6 is harder and might cause wonky steering.
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Hmm, I was very much on my own once I decided I didn't agree with what had been recommended as my size. I always suspected the 500L may be too long but Andy B seemed so sure it would be right that I went for it.
On the brochure though a nomad that looks a bit smaller than mine (shorter tt) would be ok for me, yet mine is "too small". Yet I think there are lots of happy customers who have been fine with Thorn's sizing advice. It has a bit on the Nomad leaflet I think about women liking shorter top tubes.
I was advised to raise the bars to get the bars closer. I tried this, but I prefer them at about saddle height.