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FLUX.3 Image Klein LoRA training with SimpleTuner: setup guide
Setting up SimpleTuner to train a FLUX.3 Image Klein LoRA: support status, the settings known to work, and links to the official docs. Status in SimpleTuner: supported (Base + distilled klein recipes, 24-144 GB).
About SimpleTuner
bghira's trainer; community describes it as more powerful (e.g. teacher-student regularization) but with a harder data loader setup. Sources: github.com/bghira/SimpleTuner, www.reddit.com/r/FluxAI/comments/1ogw37j/best_flux_lora_trainer/
SimpleTuner-specific notes for FLUX.3 Image Klein
- SimpleTuner recipes: rank-32 LoRA, LR 1e-4, REPA; distilled klein auto-loads a published training-assistant LoRA (strength 1.0 in training, 0.0 at validation; disable_assistant_lora to turn off)
VRAM
SimpleTuner recipes: Base from 24 GB (512px, batch 3) up to 144 GB; distilled klein at 24 GB (768px, batch 1) or 80 GB (1024px, batch 4)
Settings that work for FLUX.3 Image Klein (any trainer)
- Open weights, gated on Hugging Face: click 'Agree and access' on the model page or downloads fail with 403
- Early reception mixed; anatomy issues reported [Discord community reports (AI Toolkit / banodoco / lodestone_rock servers), Oct 2026]
- Base model sampling: ~50 steps, CFG 3.5 [Discord community reports (AI Toolkit / banodoco / lodestone_rock servers), Oct 2026]
- LoRA strength ~1.3 at inference [Discord community reports (AI Toolkit / banodoco / lodestone_rock servers), Oct 2026]
- Character LoRAs at default rank 16/32 reported weak [Discord community reports (AI Toolkit / banodoco / lodestone_rock servers), Oct 2026]
- SimpleTuner recipes: rank-32 LoRA, LR 1e-4, REPA; distilled klein auto-loads a published training-assistant LoRA (strength 1.0 in training, 0.0 at validation; disable_assistant_lora to turn off)
- ai-toolkit edit training with several control images used only one until a fix on Oct 17; update before training edit LoRAs
- A FLUX.2 dataset and recipe carried over unchanged did not work well; long upsampled prompts with JSON bounding boxes at ~2 MP sample better [Discord community reports (AI Toolkit / banodoco / lodestone_rock servers), Oct 2026]
General tips
- Gated Hugging Face models: click 'Agree and access' on each model page, or you'll get 403 errors
- Steps scale with dataset size (steps = epochs x images at batch 1)
- Common safe start: LoKr with auto rank (~64), batch/grad accumulation 4 [Discord community reports (AI Toolkit / banodoco / lodestone_rock servers), Oct 2026]
Compare with other trainers
Where to rent a 16 GB+ GPU
Cheapest 16 GB+ cards (2026-10-16 14:43 UTC) from RunPod and Vast.ai. Prices move constantly; see the live price table.
| GPU | VRAM | RunPod community $/hr | Vast.ai cheapest $/hr |
|---|
| RTX A4000 | 16 GB | $0.17 | $0.09 |
| Tesla V100 | 16 GB | $0.19 | $0.10 |
| RTX 3090 | 24 GB | $0.22 | $0.12 |
| RTX 5060 Ti | 16 GB | — | $0.12 |
| RTX 5070 Ti | 16 GB | — | $0.12 |
| RTX A5000 | 24 GB | $0.16 | — |
Sources
FAQ
Does SimpleTuner support FLUX.3 Image Klein?
Yes: supported (Base + distilled klein recipes, 24-144 GB) (see sources below).
How much VRAM do I need for a FLUX.3 Image Klein LoRA?
SimpleTuner recipes: Base from 24 GB (512px, batch 3) up to 144 GB; distilled klein at 24 GB (768px, batch 1) or 80 GB (1024px, batch 4)
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Data updated 2026-10-16. Disclosure: RunPod and Vast.ai links are referral links; ImageLoRA may earn a commission at no cost to you. unknown = not yet verified from a source.