The Ultra-shortbase D.P. tandem appears in Claud Butler's catalogues from 1951 to about 1955 in two designs: the Double Diamond (Model 48) and the Centre Bar (Model 49). The 1951 catalogue gives Reynolds 531 tubing and 26in Endrick rims.
Known components
Listed exactly as our confirmed sources give them, with the year and source for each. A part listed for one year or version may not apply to every bike, so check against yours.
Frame and fork
- Reynolds 5311951 · 48, 49 — Ebykr catalogue archive, p.12
- Double Diamond and Centre Bar tandems1953 · 48, 49 — Ebykr catalogue archive, p.14
- Double Diamond frame1954 · 48, 49 — Ebykr catalogue archive, p.14
- Double Diamond and Centre Bar designs1955 · 48, 49 — Ebykr catalogue archive, p.10
Gears and drivetrain
- 3-speed option1951 · 48, 49 — Ebykr catalogue archive, p.12
Wheels and tyres
- 26in Endrick rims1951 · 48, 49 — Ebykr catalogue archive, p.12
Catalogue appearances
| Year | Name as printed · model no. | Details | Source |
|---|---|---|---|
| 1951 | Ultra-shortbase D.P. (Double Diamond and Centre Bar) · 48, 49 | Tandems; Reynolds 531; 26in Endrick rims; 3-speed option. | Ebykr catalogue archive, p.12 |
| 1952 | Ultra-shortbase D.P. · 48, 49 | 60in overall wheelbase. | Ebykr catalogue archive, p.12 |
| 1953 | Ultra-shortbase D.P. · 48, 49 | Double Diamond and Centre Bar tandems. | Ebykr catalogue archive, p.14 |
| 1954 | Ultra-shortbase D.P. · 48, 49 | Double Diamond frame 16½ lb; Centre Bar 17½ lb. | Ebykr catalogue archive, p.14 |
| 1955 | The 'Ultra-shortbase D.P.' model · 48, 49 | Double Diamond and Centre Bar designs. (About 1955) | Ebykr catalogue archive, p.10 |
Specs are as printed in the catalogue. Years are when the model appears in a source, not exact production dates.
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Sources
Last updated 19 October 2026. Every fact on this page comes from one of these.
- Ebykr catalogue archive: Claud Butler 1951 catalogue (transcription) (p.12)
- Ebykr catalogue archive: Claud Butler 1952 catalogue (transcription) (p.12)
- Ebykr catalogue archive: Claud Butler 1953 catalogue (transcription) (p.14)
- Ebykr catalogue archive: Claud Butler 1954 catalogue (transcription) (p.14)
- Ebykr catalogue archive: Claud Butler catalogue of about 1955 (transcription) (p.10)