Cutting seatpost on Fuji D6

Triathlon Forum
1

I just bought a new D6 Pro from a shop that was closing down and got a killer deal on it. I normally ride a 57/58 and this is a 58 but when I put my fit kit numbers into it its about 4 cm too long. Anyone else had issues with these things running to big?

It was in the box when I bought it and came with both short and long seat masts. The only way to fit it is to cut the seatpost down by the 4 cm. Everything on Fuji’s website says not to cut their posts and when I called them they couldnt give me a good technical reason not to cut it, the rep just kept telling me it would void the warranty.

Has anyone cut one of these bikes off to fit it and if so is there anything special to it other than the usual SOP (tape the cut line, get the cut square, sand off the burrs and seal the cut with clear fingernail polish)?

2

bump… still looking for advice.

3

Hi, i’m pretty new to this forum. I was contacted by a friend from ASI about this post. I previously was the Design Engineer for all of ASI.

I was the designer/engineer for this as well as most ASI products released over the last few years from fuji, all the re-design of kestrel and SE bicycles. I have sense started my own company designing/engineering bicycles for the industry. Most recently, I was contracted by Rock Racing to come in and design the line for them, both carbon and the fixies.

To answer your question about the seat mast. Actually the seat mast was completely designed to be cut. I developed and engineered the layup to account for cutting down the seat mast. As well, I designed the seat post in a few different sizes. I designed a nice seat mast cutting guide but know that ASI never went into production with it. I had a few made for Rock Racing.

what you can do is carefully mark and cut the mast, ensure to cut the mast parallel to the top of the mast. if the slip-post’s lower set screw doesn’t set against the ss back plate that i designed co-molded to the mast, then have your shop order the smaller version slip-post (seat post). I cut down my D6, it rides most excellent. The seat mast length and it’s cut-ability, as well as the selection of being able to use different size slip-post (seat post) was the original design intent.

Now ASI as a company might not be covering the D6 under warrenty if the mast is cut, which is silly as the bike was designed to have the mast cut? The warrenty of such a cut that is there perrogative (ASI) as a company, but that’s up to you. p.s. I have confirmed that the layup wasn’t changed after i left ASI, as I continue to use the same factory for my manufacturing.

All the best, Shane

p.s. let me know if you need anymore info…

4

Sell it.

5

My friend rides a D6 and had the same problem, he had the seat post cut and has loved it ever since. Hope this helps.

6

I finally sized it out with my fitkit numbers and cut it. works fine and is fast as hell!

thanks for your help ya’ll.

Vintage Mark

7

Just to clarify as an ASI representative, the D6 seat mast is NOT designed to be cut nor is it covered for warranty if it is cut.

There are 2 sizes of posts that your Fuji Dealer can supply you to help you with your fit.

Hope that helps everyone.

If anyone has any Fuji or Kestrel questions, always feel free to contact me.

Thanks!

8

Is the Fuji D-6 UCI legal?
I understand there is a 3:1 ratio rule that relates to the seatpost dimensions??
Appreciate any feedback on this, thanks.

9

It is.

10

Hey, Steve,

I do not work for ASI any longer as you know. I was the Designer and did the engineering for the D6 as well as many others while at ASI. I know you had just moved from part & accessories to kestrel brand management when I started designing the bike, as well not a part of its D6 process.

I did want to correct you concerning the design and engineering of the bike as the bikes designer and engineer. --the bike was in fact designed to have the mast cut. Just to state the facts–

All testing reports, as well as layup post production FEA analysis that was conducted at Martec while I was there for ASI back in Aug of 2008, I would be happy to share with you, if you need to see for yourself. P.s. copies were left with ASI.

Please feel free to contact me if you need further clarification: scfedon@yahoo.com

I am not telling the consumer that he should do it, I am telling the consumer the design intent, as well as what I have done as its designer and an owner of one who cut the mast down and if he does it, how to correctly cut it.

In addition, our Rock Racing PCT used the D6, and continues to use the D6, with the masts cut as you also know. The consumer was already told by someone at ASI that cutting the mast would void his warranty. The consumer has now come to all of us on Slowtwitch. He seems to be in great knowledge of what to do if you read his first post; he is looking for others whom have done the same so that he can fully enjoy the bike. I think we should trust that the consumer understands, but still wants to own the bike or do the unthinkable trade it in for a bike which he can make to fit his body.

If ASI has had Martec change the layup for whatever reason, which I know they did not, then simply explain to us all that ASI had changed the layup design because they decided that it would be best for ASI. We understand that happens to designs all the time and would accept it.

If ASI did change, then why did ASI forget to enforce in QC inspection the missed 2.5mm holes for the rear brake centering screws? or how about the new rear brake cavity bonded section piece, that would allow the housing to move more freely for proper brake accuation? These were all revisions i made in sept just before i left ASI that were never made? these would be revisions that make the bike closer to how the production was suppose to have happened and therefore be a completed production piece?

Please let us all know if ASI has in fact changed the layup, if so, then we all can be satisfied and look for another bike company to purchase from that would be smart and have a bike that was customizable, especially for the price. Adjustability is the key, not conformability which was in fact the design intent.

If you need to contact me further, you have my number, 814.232.0660. As well as my email above. As a reminder—I am a bonded and insured Design Engineer in the State of California. I am a senior member of the Society of Manufacturing Engineers and Plastics Engineering Society #14461043. Am well educated in composites and composite design to discuss design and any structural applications pre or post production. Even though it is well known that you and I do not see eye to eye.

Thanks, shane

11

Hey,

yes, i do agree with Steve here! :slight_smile:

when the bike was designed, i took great consideration to ensure that the 3:1 rule, FC rule (front center), frame dimensional (8cm) rule were all up held, addtionally ensurng that the 5cm seat rule would work for UCI teams, but that Tri guys would be able to have a more appropriate forwad positioning.

Unfortunately i do not agree with all of the rules, but try to just work with them while hopefully we in the industry can push for such changes.

All the best, shane

12

Thanks guys for the information :slight_smile:
.

13

Hi Steven H - I just came home with a BRAND new D6 Pro (58 cm) yesterday afternoon. However, I only received one seat post and I’m having the same problem as other folks on the forum – the seat is still too high. I’d like to avoid cutting the seat mast if at all possible. What are the sizes of the two seat posts that are available form Fuji? Does the smaller size have a shorter minimum or just a shorter maximum height? I found no mention of this on the Fuji website. Thank you! Jorge

14

Have your shop call our inside guys and I think they have the shorter post in stock. Do NOT cut the post that you have.

15

Good day to all, I am also riding a D6 3.0 size XS 50 cm , Im 5ft 5inches tall, recently i bought an adamo saddle have it installed on its mast i find saddle height a little higher than it was before with an oval saddle.for a size xs at 50cm at 561cm total length can i consider reducing or cutting the seatpost, need some inputs wtih this.Thanks
.

16

My shop cut it np
.

17

What tool did they use sir? or are there special equipment in cutting a carbon fiber and how long is it in cm?sorry for asking too much…have a good day!!

18

Do you have the short seatmast or long?

Im 5,5 riding a 48cm and my short post one is actually lifted

19

good day viper, i only received one seatmast, i dont know exactly if it is short or long.

20

What tool did they use sir? or are there special equipment in cutting a carbon fiber and how long is it in cm?sorry for asking too much…have a good day!![/

They used some kind of grinding tool but you can use anything