"Gravel" Bike Assembly

For discussions about bikes and equipment.
guer_gal
Posts: 3
Joined: 15 May 2019, 3:50pm

"Gravel" Bike Assembly

Postby guer_gal » 15 May 2019, 4:55pm

Hi everyone, I'm new on the forum, I start by saying that I'm a beginner and I'm not English, so I apologize in advance for any typos or ignorance in the world of bicycles.
I bought this frame online at a very low price, which was sold to me as an aluminum cyclocross frame, I was surprised when I received it because I discovered it was made of carbon, it is a 18" size and weights 1160 grams but it doesn't look like a Cyclocross frame at all... anyway I bought a carbon fork and 700c wheels, avid bb7 disc brakes, an on one midge handlebar and sunrace 3x8 brake levers, do you think the frame geometry is good for the components? I am gonna use the bike in the city on very bumpy roads. Thank you for your help
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Brucey
Posts: 35628
Joined: 4 Jan 2012, 6:25pm

Re: "Gravel" Bike Assembly

Postby Brucey » 15 May 2019, 8:53pm

guer_gal wrote:….. do you think the frame geometry is good for the components? ....


you/we don't know anything much about the frame geometry, and given that you didn't get the frame you expected from the vendor, I'd guess they don't either.

The frame is probably designed with a particular wheel size and length of fork in mind; if what you buy deviates from that by very much the steering and the riding position might well be badly affected.

So you need to do some very careful measurements and/or just suck it and see.

cheers
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guer_gal
Posts: 3
Joined: 15 May 2019, 3:50pm

Re: "Gravel" Bike Assembly

Postby guer_gal » 15 May 2019, 10:53pm

What are the most important measurements I should do? I tried, as suggested, to mount the fork and the wheels, as you can see the space that remains between the rear stay and the wheel is less than the space that remains between the fork and the wheel, in your opinion it is a frame made for wheels from 27.5 instead of 700?
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gregoryoftours
Posts: 1016
Joined: 22 May 2011, 7:14pm

Re: "Gravel" Bike Assembly

Postby gregoryoftours » 15 May 2019, 11:19pm

Yes the rear is definitely not designed for a 700C tyre. Going by how it looks it is designed for a wide tyre on a smaller wheel. Is the front wheel sat in the fork dropouts properly? It looks very much over to one side. It's definitely not a cyclocross frame.

guer_gal
Posts: 3
Joined: 15 May 2019, 3:50pm

Re: "Gravel" Bike Assembly

Postby guer_gal » 16 May 2019, 12:00am

it is just as it seemed to me, I will opt for another frame ...

Brucey
Posts: 35628
Joined: 4 Jan 2012, 6:25pm

Re: "Gravel" Bike Assembly

Postby Brucey » 16 May 2019, 12:14am

if you have a frame that is meant for 27.5 (584) wheels with fat tyres then a set of 700C wheels with ~35-40mm tyres will also fit reasonably well and may be a lot better for urban use. If the fork is to go in a frame that might instead accept a suspension fork, it tends to be taller than is required for tyre clearance alone; that is quite normal.


On a flat floor with the fork and wheels in, you can drop a plumbline through the middle of the BB and measure the offset from the centreline of the seat tube, and you can carry out some basic trigonometry and work out the seat angle.

By eye it looks like the head angle is quite a bit slacker than the seat angle, and the seat angle looks pretty steep; I certainly wouldn't want to use a shorter fork, lets put it like that. You might be able to make this all work OK but there may be intractable fit problems; if the frame is meant for flat bars it may be much longer than is good for use with dropped bars, unless a very short stem is used.

FWIW frame angles and so forth are just a means to an end; the end is to be able to get your contact points in the right place relative to one another. Having the right frame geometry helps that no end but if you can fit a seatpin with enough layback even a frame with a seat angle that is too steep can be made to work.

cheers
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Bmblbzzz
Posts: 2832
Joined: 18 May 2012, 7:56pm
Location: From here to there.

Re: "Gravel" Bike Assembly

Postby Bmblbzzz » 16 May 2019, 9:12am

guer_gal wrote:Hi everyone, I'm new on the forum, I start by saying that I'm a beginner and I'm not English, so I apologize in advance for any typos or ignorance in the world of bicycles.

Your English and typing is better than many native English speakers, so I really wouldn't worry about that. :D

As for the bike, I guess that now you've started building it up, it's too late to ask for a refund or a swap for the aluminium cyclocross frame that was advertised. In any case, as you were sent the wrong frame first time, who knows what they might send you if you ask for a swap...