What type of frame

General cycling advice ( NOT technical ! )
eddienunhead
Posts: 11
Joined: 3 Mar 2019, 2:06pm

What type of frame

Post by eddienunhead »

Dear all
Managed to get this frame the other day, see attachment, it's a 1992 roberts but has a 2cm slope towards the headtube. Would this be something common for road bikes in the 90s or is it a time trail frame, although the slope is not as steep as images I have seen of tt bikes, the wheels are both 700c. Any help appreciated thanks Eddie
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20230320_175019.jpg
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willcee
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Joined: 14 Aug 2008, 11:30pm
Location: castleroe,co.derryUlster

Re: What type of frame

Post by willcee »

Yes i would guess TT , but maybe so it could be used with a 650 [26 ''] front wheel in a TT and a 700 which looks highly close to the front yoke , ...when riding 'normally'.. Obviously a special tailored build Roberts may have details if you could supply the frame number and if theyre still trading.. will
rogerzilla
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Re: What type of frame

Post by rogerzilla »

Assuming it has its original fork, it must be deliberate: Roberts wouldn't have made a mistake like that. My guess is that it was made for a junior racer who wanted (and, being young, was thin and flexible enough to use) a very low position.

Jim Bundy track bikes, rare here (I may have the only one!) but common in Australia, also often have a slight forward slope. Trackies tend to want very low bars.
cyclop
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Location: Dumfriesshire

Re: What type of frame

Post by cyclop »

I guess you could put a quill stem/threadless converter on,enabling options of either drop bars at a more suitable height or even conversion to riser/flat bars enabling you to use the bike comfortably.What do you ride normally?
rjb
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Location: Somerset (originally 60/70's Plymouth)

Re: What type of frame

Post by rjb »

Those low profile frames became a fashion item for time trials during the 1990's. Like other fashions they didn't last. :wink:
That Roberts looks like it was made for a smaller front wheel. The toe overlap appears tight with the current wheel in there.
BTW what's the decal on the top tube. Does it identify the original owner. :?:
Last edited by rjb on 21 Mar 2023, 8:52am, edited 1 time in total.
At the last count:- Peugeot 531 pro, Dawes Discovery Tandem, Dawes Kingpin X3, Raleigh 20 stowaway, 1965 Moulton deluxe, Falcon K2 MTB dropped bar tourer, Rudge Bi frame folder, Longstaff trike conversion on a Giant XTC 840 :D
andy753
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Joined: 13 Jul 2013, 12:43pm

Re: What type of frame

Post by andy753 »

Wow... a lovely classic! I remember a few of these 'sloping top tube' designs from the late 80s and early 90s - at Herne Hill track in London. I suspect this might have been a track bike BUT the fork suggests it might have been a time trial bike as others have suggested. It's great that you are preserving a slice of cycling history!
eddienunhead
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Joined: 3 Mar 2019, 2:06pm

Re: What type of frame

Post by eddienunhead »

Thanks for the replies, there is no name on the bike and yes a 650 front wheel would work. Thanks
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Mick F
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Re: What type of frame

Post by Mick F »

With the wheels removed, and the front and rear dropouts supported level with each other, is the top tube still sloping?

If so, it's either a TT frame, or the front fork isn't original.

On my Mercian, the serial number is stamped on the bottom of the BB shell, it is also on the fork steerer tube .......... meaning the fork is matched to the frame.

Any clue with your Roberts?
Mick F. Cornwall
eddienunhead
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Joined: 3 Mar 2019, 2:06pm

Re: What type of frame

Post by eddienunhead »

I will have a look, and yes the top tube still is sloping when wheels are out but only by a little.
rogerzilla
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Joined: 9 Jun 2008, 8:06pm

Re: What type of frame

Post by rogerzilla »

The main problem with a top tube sloping forwards is that older/fatter/less flexible riders - by which I mean everyone except a few young racing whippets in their teens or 20s - will need a stem with an extra-long quill to be comfortable, and it can look gawky.
20220514_093907.jpg
iandusud
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Joined: 26 Mar 2018, 1:35pm

Re: What type of frame

Post by iandusud »

I would suggest that it is definitely a road TT bike. Not a track frame going by the braze ons. The tight clearance and toe overlap of the front wheel are in keeping with TT bikes of that time and I therefore think it was designed for a 700c front wheel. As already said these sloping top tube TT bikes were very common in the late 80s and early 90s.
pwa
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Re: What type of frame

Post by pwa »

In the days when quill stems were normal for road racers (including TTers), you'd commonly hear racy types complaining that they couldn't get the stem quite as low as they wanted it. Having a horizontal top tube, and with most seat posts not all that long, there could be a tension between having the bars as low as you wanted them without ending up unable to get your bum high enough with your preferred Campag seatpost. I'd guess this frame might have been commissioned by someone who wanted to get particularly aero, maybe with local 10 mile TTs in mind. I achieved the same aim by having a horizontal top tube, but with the seat tube extended above it by 2cm, which to me looked neater.
Jdsk
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Re: What type of frame

Post by Jdsk »

Mick F wrote: 21 Mar 2023, 9:51am With the wheels removed, and the front and rear dropouts supported level with each other, is the top tube still sloping?
...
eddienunhead wrote: 20 Mar 2023, 8:41pm ... the wheels are both 700c.
If the front and rear tyre heights are the same won't the top tube then be at the same angle as at present?

Jonathan
Barrowman
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Re: What type of frame

Post by Barrowman »

I used to ride a road/TT bike from the era. 700c both ends and the pedal overlap was lethal . Fag paper clearances, ( Flying Gate) and I think 37" wheelbase.
Rear Entry fork ends at the back with integral gear hanger. Top tube was 'straight/parallel' not 'sloped' .
I do recall the slopers of the era, some with 650 c front wheel. Would a brake go down to a 650 on your frame?
slowster
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Re: What type of frame

Post by slowster »

Although in the photograph the bike has drop bars, I expect that it was originally fitted with bullhorn style bars and tri-bars, e.g. as shown in the photograph below of Kevin Dawson, who won the British Best All Rounder in the year that frame was built. The single bottle cage boss on the down tube was the norm for such bikes.

Image
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